Script Compilation: Follow-Up, Link, Side Effect, Symptoms

Script Compilation: Follow-Up, Link, Side Effect, Symptoms

This post will contain transcripts of my videos devoted to explaining some of the quirky GURPS modifiers.

Follow-Up and Link

In this video, I would like to talk about the Follow-Up and Link modifiers – how they work, and how follow-up and linked effects work, and what’s even the difference. Both of these modifiers are very often used when building abilities, and both of them can raise some questions.

The Follow-Up enhancement appears on page 105 of GURPS Basic Set. It has a variable value. It is used to make attacks that are delivered by another attack. Thus, you will have a carrier attack and a follow-up attack. Poison on a dart, explosive bullets, flaming swords – all this is usually done with the follow-up enhancement. Follow-Up is a “penetration modifier”; you cannot combine it with other penetration modifiers (although the carrier attack can have them).

The carrier attack can be a natural weapon, a manufactured weapon, or an Innate Attack. The follow-up attack only usually lists only its damage amount and type, and most of the remaining properties depend on the carrier attack. The follow-up attack hits only if the carrier attack hits, and if the carrier attack penetrates DR, then DR has no effect on the follow-up attack. If the carrier attack does not penetrate DR, then the follow-up attack still happens, but outside the victim, so it is affected by DR normally.

Follow-up effects that occur internally never inflict knockback or blunt trauma – even if their damage type usually does.

If the carrier attack is an Innate Attack, the cost of Follow-Up depends on the modifiers on the carrier attack. The cost of Follow-Up equals the sum of the costs of whichever of the following modifiers apply to the carrier attack: Always On, Aura, Cone (why is Cone here, but not Area Effect?), Drifting, Emanation, Emergencies Only, Extra Recoil, Guided, Homing, Increased Range, Jet, Limited Use, Malediction, Melee Attack, Preparation Required, Rapid Fire, Reduced Range, Takes Extra Time, Takes Recharge, Unconscious Only, Uncontrollable, or Unreliable. If none of these modifiers apply to the carrier attack, Follow-Up costs +0%. Note that the Follow-Up attack itself cannot take any of these modifiers. Only its carrier attack may have them.

If the carrier attack is a natural weapon, such as Claws or Teeth, Follow-Up is a +0% enhancement. (Exception: On a passive carrier attack such as Spines, Follow-Up is a -50% limitation.)

GURPS Power-Ups 4: Enhancements introduced Follow-Up, Universal, +50% that allows your follow-up attack to piggyback on any unarmed or weapon attack you make, whether melee or ranged – but not on an Innate Attack.

So, let’s make some example to illustrate how it works.

Example #1: Flaming Fists

Let’s build an ability that covers the user’s fists in flames. This is going to be a magical ability that also provides illumination. This is how it’s going to look like.

Burning Fists [5]: Burning Attack 1d-1 (Follow-Up, Punch, +0%; Magical, -10%) [4] + Illumination (Magical, -10%) [1].

I should note that abilities of this kind do not harm the user. Since we are enhancing a natural attack – the punch – Follow-Up is a +0% modifier. This ability covers all hands, but does not affect any other natural weapons, such as kicks and bites. To have burning kicks, you’d have to create an identical ability and replace Follow-Up, Punch with Follow-Up, Kick. However, that doesn’t seem very cost effective – doing that would result in you spending 10 points, when Follow-Up, Universal, +50% would only increase the cost by 2 points and extend this ability to all weapons, whether natural or manufactured. I suggest treating such extensions as a +10% modifier. So, Follow-Up, Punch and Kick would be a +10% modifier, while Follow-Up, Natural Weapons would be a +30% modifier to cover punches, kicks, bites, head butts, elbow strikes, knee strikes, and everything else. Basically, this is a downgraded version of a Melee-Range Aura that would result in a +50% modifier, but it cannot be used passively.

But rule-tweaking aside, let’s see how it would work in action. In this example, we will have our hero deal 1d damage with his punch against a target that wears DR 2 armor.

Case #1 – the hero rolls 4 damage. He penetrates DR 2 and deals 2 injury with his punch. Since the carrier attack penetrated DR, the burning fist effect does not have to overcome it! In addition to 2 damage from the punch, the hero rolls 1d-1 and deals, for example, 3 points of burning damage.

Case #2 – the hero rolls 1 damage. He fails to penetrate DR 2, but the follow-up still works, but now it works outside the target and hence is affected by DR. He rolls 1d-1 burning damage and gets 4. Burning damage penetrates DR 2 and deals 2 points of damage to the target.

Case #3 – the hero rolls 1 damage. He fails to penetrate DR 2, but the follow-up still works. He rolls 1d-1 burning damage and gets 1. Burning damage fails to penetrate DR 2 and the target is unharmed.

Case #4 – the target now wears DR 2 armor and has natural DR 2 with Tough Skin. The hero rolls 3 damage. He penetrates the armor DR, but does not penetrate the natural DR. Thus, the flaming effect works between the two layers of DR. He rolls 1d-1 and gets 4. These 4 points of burning damage are only affected by the natural DR 2 and result in 2 points of injury, because the carrier attack has penetrated the outer DR level.

Example #2: Explosive Arrow Spell

In this example, I will combine two Innate Attacks together with Follow-Up.

The carrier attack will be as follows: Impaling Attack 1d (Guided, +50%; Magical, -10%; Reduced Range, 1/10, -30%; Takes Extra Time 1, -10%) [8].

The follow-up attack will be as follows: Crushing Attack 3d (Explosion 1, +50%; Follow-Up, Impaling Attack, +10%; Magical, -10%) [23]. Why is Follow-Up +10%? Because Guided, +50% plus Reduced Range, 1/10, -30% and Takes Extra Time 1, -10% give us +10% when added up together.

So, now, let’s see it in action again. The target is the same unnamed character who is wearing DR 2 armor.

Case #1 – the impaling attack deals 5 points of damage, penetrates DR 2. Thus, the explosive follow-up attack not only ignores DR, but is also treated as an internal explosion that is treated as a hit to the vitals for triple damage. Internal explosions hurt a lot!

Case #2 – the impaling attack deals 1 point of damage and fails to penetrate DR 2. The explosion still occurs, but outside the target. It uses the normal explosion rules and is affected by DR as normal.

Case #3 – the target how has natural DR 2 with Tough Skin in addition to DR 2 armor. The impaling attack deals 3 points of damage, penetrating the outer DR layer and then explodes between layers. What happens? Honestly, I do not know. Perhaps, this is treated as a contact explosion, not as an internal explosion, or perhaps it is better to just keep things simple and treat it as a normal explosion. This is just something of a though experiment. And don’t even ask me about how it interacts with fragmentation – I refuse to think about it and would just treat it as a normal hit.

An addition rule interaction to keep in mind is Blunt Trauma and Edged Weapons from page 102 of GURPS Low-Tech. What is the carrier attack were a Cutting Attack and not an Impaling Attack? Then the follow-up effect would only count as internal if the cutting attack managed to overcome twice the armor’s DR. Again, this is one of the details that would only come into play in gritty games and very specific situations.

Example #3: Poison

Follow-up is often used for poisons. Usually, they are carried by a natural attack, so Follow-Up will almost always be a +0% modifier. Defensive poisons that are carried by Spines make Follow-Up a -50% limitation, this is a special case. Follow-up poisons work when introduced into the bloodstream. But Follow-Up is incompatible with Blood Agent, -40%, as both as penetration modifiers. However, poison examples in all the GURPS books just use follow-up without anything to indicate the fact that it has to get into the bloodstream. Let’s illustrate what I mean here.

For example, we have Toxic Attack 1d-1 (Follow-Up, Sharp Teeth, +0%) [3] and a bite attack that deals 1d cutting damage; and the same target with DR 2.

Case #1 – the bite deals 4 points of damage and penetrates DR 2. In this case, we will ignore the edge protection rules I mentioned before. So, the target takes 2 points of cutting damage and then the follow-up poison deals 1d-1 toxic damage ignoring DR.

Case #2 – the bite deals 1 point of damage, failing to penetrate DR 2. And the poison deals no damage regardless of how well you roll your 1d-1 toxic damage. From what I understand, this is why that happens – the poisoning happens outside the target, so the armor is affected by the poison, not the target. And armor is an inanimate object, so it cannot be affected by poison, that’s why there’s no penetrating damage even if you roll 5 toxic damage. You just have to use common sense when toxic and fatigue damage is in question. I guess this is something of a special feature. Page 381 of GURPS Basic Set talks about this.

You can apply follow-up to an Affliction instead of an Innate Attack. An Affliction with follow-up will get a chance to affect the target even if the carrier attack does not penetrate DR, but will be penalized by this DR. But now that I think about it – some poisons can be represented with Affliction and not Toxic or Fatigue Attack, so you might want to apply common sense again. If the carrier attack has Malediction, then the follow-up only affects the target if the target fails to resist and does nothing if the carrier attack fails to affect the target.

So, is everything clear with Follow-Up? I hope it is, because it is a quite wonky modifier. Now, let’s talk about Link. This enhancement lets you use two or more advantages at the same time. For +10%, your abilities are permanently linked together – you cannot use them separately. For +20%, you can also use them separately. You must add this enhancement to all the abilities you wish to link. A set of linked advantages can mix the +10% and +20% versions of Link. The advantages with the +20% level work both as part of the Link and on their own. Those with +10% level are only available when using all of the linked advantages at once. When a set of advantages has Link at the +20% level, the user can specify that he’s using one, some, or all of them, in any combination.

If you link two attacks into one and give them identical Malf., 1/2D, Max, Acc, RoF, Shots, and Recoil, you can treat them as a single attack with one attack roll but separate rolls for damage.

So, when do you use Link? This is useful for abilities, such as toxic clouds. It’s both a Toxic Attack and an Obscure that penalizes vision. Also, sometimes you have to use it just because you cannot do it with Follow-Up! Link, unlike Follow-Up, is not a penetration modifier, and thus can be combined freely with other modifiers.

For example, let’s create an ability that lets us fire a metal projectile and can optionally be electrified. The projectile is Piercing Attack 1d (Link, +20%; Reduced Range, ½, -10%) [4] + Burning Attack 1d (Link, +10%; Reduced Range, ½, -10%; Side Effect, Stunning, +50%; Surge, Arcing, +100%) [13]. See? First, to make it a single attack, I had to give them the same range. I also gave them an asymmetrical link. Piercing Attack can be used separately, but Burning Attack cannot be used without the Piercing Attack. You wouldn’t be able to do it with Follow-Up, because Follow-Up is incompatible with both Side Effect and Surge, Arcing. Even though these attacks are used with a single attack roll (and can be defended against with a single defense roll), both of them have to overcome DR separately.

Finally, there’s a Frequently Asked Question that I have to mention here:

5.2.6. How do you Link an attack onto a mundane weapon, or even multiple weapons?

You buy a Link, probably the +20% one. Then you add an Accessibility to reflect the weapon category size of applicable weapons. This is indeed cheaper than the Follow-Up case, because it doesn't overcome DR if the primary attack does. Please note that Linked attacks should still have the appropriate Range/Reach, Acc etc.

And that’s it. I hope that now you understand Follow-Up and Link better. Despite looking simple, they aren’t actually that easy to use and have many edge cases.

Side Effect and Symptoms

I would like to talk about the Side Effect and Symptoms enhancements, as they may seem similar, but they accomplish different things and have some rule quirk that might confuse a new player or GM.

Let’s start with Side Effect. This is an enhancement that is only applicable to an Innate Attack and that is incompatible with any penetration modifiers other than Armor Divisor and Surge, Arcing that was added in GURPS Power-Ups 4: Enhancements. If any damage penetrates the target’s DR, he must make a HT roll, at -1 per 2 points of penetrating damage, or suffer a side effect. And here’s something important that many probably do not know about – in the most recent printing of the GURPS Basic Set, penetration damage was replaced with injury! So, now you calculate injury first, then apply a side effect. This is a sneaky change that significantly changes the way this enhancement works, making it interact with damage types, hit locations, Injury Tolerance, and Vulnerability, so please do not forget it. You won’t even be able to find this change on the errata page.

If you are modifying ST-based attacks as per the rules from GURPS Power-Ups 4: Enhancements or using Natural Weapons from Pyramid #3-65, you can apply Side Effect to them as well.

GURPS Powers says that you may also apply the Based on (another attribute), +20% enhancement to replace the HT resistance roll with, for example, Will, Perception, or DX. This is useful for some supernatural attacks.

So, what side effects are legal and how do you calculate the enhancement value? Side effects are chosen from the list you can find under Affliction – the valid choices are stunning, Attribute Penalty, and Incapacitation. GURPS Power-Ups 4: Enhancements also added new enhancements for Affliction, and all of them can be used for Side Effect – Density Increase, Itching, and Slower Move. The cost of Side Effect is base +50% plus the cost of the Affliction enhancements. Since stunning is the default Affliction, it does not increase the cost of Side Effect. Thus, Side Effect, Stunning will be a +50% enhancement, not a +60% one. Deafness is a +20% enhancement for Affliction, so Side Effect, Deafness will be a +70% enhancement.

Here’s some food for thought – why can’t you have an Irritant Side Effect? Honestly, I have no idea, I think this is just an oversight. If Itching and Slower Move are valid, why can’t Moderate Pain be valid? Or Nauseated? Personally, I would allow Irritant Side Effects. Negated Advantage also seems like it should be a valid choice. Advantage, Negated Disadvantage, Coma, and Heart Attack probably should stay out of the list.

You may specify more than one side effect. If the victim gets a single resistance roll against all of them, treat them as a single Side Effect enhancement, totaling their cost. If the victim must resist each effect individually, take a separate Side Effect enhancement for each effect.

How long does Side Effect last? Stunning wears off normally, while other effects last (20 - HT) minutes, minimum 1 minute. If Incapacitation is combined with other effects, the other effects last for another (20 - HT) minutes after the Incapacitation wears off. I’m pretty sure that you can apply Extended Duration and Reduced Duration to modify this duration.

Also, if Afflictions can have secondary effects that only happen if you fail your resistance roll by 5 or roll a critical failure, I believe that Side Effects can be secondary as well. I see nothing broken in this rule interaction, and I have used this in some of my ability write-ups.

I have seen people use Side Effect with the No Wounding limitation, but I think that it makes no sense. No Wounding removes any injury, and injury is what causes the Side Effect. Even if you track virtual injury that isn’t actually injury, I think that it’s an unnecessary complication. Blunt Trauma also doesn’t count as injury for the purpose of Side Effect.

So, let’s have a couple of examples.

Example #1 – Phlogiston Discharge

This is a Sorcery conversion of a spell from Pyramid #3-25, and it is built as follows:

Burning Attack 1d (Nuisance Effect, Behaves erratically around conductors, -5%; Sorcery, -15%; Surge, Arcing, +100%; Side Effect, Stunning, Secondary Paralysis, +80%) [13/level].

I chose this as an example because it has both Surge, Arcing, and a Side Effect with a secondary effect. Side Effect costs +80% because +50% is the base cost, stunning is free, paralysis is +150% divided by 5 for being a secondary effect. +50% + 30% = +80%.

In this example, we will have a human victim with HT 10 wearing DR 3 plate armor.

We cast Phlogiston Discharge and roll 3 damage. Since this spell has Surge, Arcing, it treats conductive metal armor as DR 1, thus we deal 2 points of damage to the victim. There is no wounding multiplier, so he takes 2 points of injury and rolls against HT-1 to resist the side effect. If he rolls, for example, 11 or 12, then he is just stunned and will be able to recover normally. If he rolls 15 or higher, then he is paralyzed for 10 minutes, because 20 – HT 10 = 10 minutes, and then is stunned normally.

Example #2 – I have no idea what to call this ability, this is just a thought experiment.

Small Piercing Attack 2d (Based on Will, +20%; Side Effect, Paralysis and Attribute Penalty, DX-4, +240%) [22].

Here we have a human victim with Will 12 wearing DR 3 plate armor. We use this ability and roll 7 damage, targeting the torso. 4 points of damage penetrate the DR and due to the wounding multiplier are reduced to 2 points on injury. The victim rolls against Will-1, not HT-1, and rolls 14, failing to resist. He becomes paralyzed for 8 minutes, because 20 – Will 12 = 8, and after paralysis wears off, he is at -4 to DX for 8 more minutes.

But what if we targeted the skull instead? The same 7 points of damage would have to overcome DR 3 from armor and the additional DR 2 of the skull, resulting in 2 points of penetrating damage. However, the skull wounding multiplier would turn that into 8 points of injury, so the victim would have to roll against Will-4 to resist, not Will-1.

I think that now everything should be clear. Side Effect is a very flexible enhancement that can be used in many abilities. So, let’s talk about Symptoms now. Symptoms is yet another enhancement that can be applied to an Innate Attack, modified ST-based damage as per the rules from GURPS Power-Ups 4: Enhancements, or Natural Weapons from Pyramid #3-65, and nothing else.

Symptoms cause certain effects when the cumulative damage from the modified attack exceeds a fraction of the victim’s basic HP or HP. There is no roll to resist, that’s why the book suggests limiting Symptoms to attacks with low damage. Yet again, the No Wounding limitation is incompatible – the victim must lose HP or FP; and blunt trauma does not count for the purpose of Symptoms.

Symptoms effects are chosen from the Affliction enhancements. The valid options are Advantage, Attribute Penalty, Disadvantage, Irritant, and Negated Advantage. GURPS Power-Ups 4: Enhancements adds Itching, Density Increase, and Slower Move as options. Since Advantage is on the list, I would also add Negated Disadvantage from GURPS Powers. You should note that Incapacitation is not available, according to the Basic Set, but some premade abilities in GURPS Powers use, for example, Paralysis as a Symptom, which counts as an incapacitating effect. So, incapacitation is allowed after all.

If the threshold for the Symptom is 2/3 the victim’s basic HP or FP, use the cost under Affliction. If the threshold is 1/2 basic HP or FP, double this cost. If it’s 1/3 basic HP or FP, triple this cost. Unlike Afflictions, Symptoms abate only when the damage that caused them is healed over the threshold.

For example: Moderate Pain is worth +20% as an Affliction, and as a Symptom that occurs when the victim has lost half 2/3 of his HP to an Innate Attack, it is a +20% enhancement. As a Symptom that occurs when the victim has lost half 1/2 of his HP to an Innate Attack, it is a +40% enhancement. As a Symptom that occurs when the victim has lost half 1/3 of his HP to an Innate Attack, it is a +60% enhancement.

An attack can have multiple Symptoms. For example, it could cause moderate pain after the victim has lost 1/3 of his HP to the attack, and cause drunkenness after the victim has lost ½ of his HP to the attack. The effects are cumulative. Thus, if you want a progressive effect, you can, for example, have Symptoms, 1/3 HP, -2 to DX, +60% and Symptoms, ½ HP, -2 to DX, +40%. When the victim loses half of his HP to this attack, he will have -4 to DX, not -2. For conditions such as pain, I suggest paying only the difference between the different degrees of severity. This is not RAW, but common sense tells me that this is how it should work.

Symptoms are very useful when creating attacks that represent poisons and diseases, but they can be used for other abilities as well. You could have, for example, a supernatural burning attack that gives the victim progressively worse levels of Berserk. It could also work for cold attacks it could be a non-incendiary burning attack or a fatigue attack with Freezing that gives -2 to DX after the victim has lost 1/3 of his HP, -2 to DX and Numbness after the victim has lost ½ of his HP to the attack, and paralysis after the victim has lost 2/3 of his HP. Get creative! But be careful with using Advantages as Symptoms, I feel like that can result in some broken stuff.