Reaction
Reactions are an uncommon stat found on a handful of cards. They serve as alternative ways for these cards to trigger besides their 
Counter reaching 0. In many cases, cards with Reactions don't even have Counters at all, and thus can only trigger via the Reaction.
Information and Strategy
Reactions are found on both player and enemy cards. Unlike the usual Counters, a card with a Reaction will trigger immediately whenever some condition is met. A reacting card triggers identically to one triggered by its Counter: it attacks the front enemy in the opposing row and uses its effects (if any). However, some reactions like the Smackback keyword cause the card to trigger against a specific target instead of the front enemy, although it still uses its effects as normal.
Although Smackback is the most common Reaction, it is far from the only one. All Reactions are written in orange ability text to indicate what triggers the Reaction, while any other abilities the card may have are colored normally. For instance, Mega Mimik has the orange text "Trigger when an ally in the row attacks," indicating its trigger condition, and "Lose 1 
Scrap" in normal text, indicating that this is an ability unrelated to what causes the Reaction.
Preventing Reactions
The nature of Reactions makes them exceedingly dangerous to offensive Companions, who tend to have low 
health. A card with Smackback is theoretically able to damage any card on the player's field regardless of position, as long as that player card hits it. There are three different ways to prevent a card's Reaction from working, even if the conditions are met.
Snowed cards can never trigger under any circumstances, and this prevents their Reactions from working. This includes if the card would react to a hit that inflicts it with Snow; for instance, Snoof attacking a Spike Wall will not trigger the latter's Smackback.
Inflicting 
Ink on a card negates all its effects, including any abilities it has that would trigger Reactions. If the card has just a Reaction and no Counter, it will never be able to trigger while Inked. Like Snow, the card will also not react to any hit that inflicts it with Ink. For instance, Maw Jaw triggers when hit by anything. Using the Flask of Ink on it counts as a hit (since the Flask of Ink has an 
attack icon), but because it Inks Maw Jaw it cannot react.
Finally, a card cannot react if it is killed by whatever would cause it to react. This sets counterattack Reactions apart from 
Teeth, which will damage an attacker even if the card with Teeth is killed by the hit.
Reaction Interactions
Counters and Reactions are independent from each other. If a card has both a Counter and a Reaction, the Reaction will not cause the card's Counter to reset when triggering.
If a card with 
Frenzy has a Reaction that causes it to trigger against a specific target (such as Smackback), it will stop attacking if the target is killed in the middle of Frenzy attacks. However, if it also has Barrage or Aimless, it no longer triggers specifically against its target. It will attempt to trigger against the intended target, but it will also abide by its ability's targeting; for instance, a card with Barrage and Smackback will react against the entire row that its attacker occupies. Any card that has one of these abilities can use all its Frenzy in one reaction, even if the intended target is killed partway through the attack. Uniquely, a card with Longshot can still trigger appropriately against its Reaction's target (instead of always hitting the furthest enemy), but it can still use all its Frenzy if the target is killed.
Spice and 
Frost are only removed once all attacks are finished and no more Reactions are being triggered. This means that if a card with a Reaction triggered by being hit (such as Smackback or Maw Jaw's Reaction) hits another card with such a Reaction, the cards will repeatedly take turns hitting each other, but their Spice and Frost will only clear once one (or both) of the cards is destroyed. However, if each card is unable to kill the other (such as if they have 0 or less attack, perhaps due to Frost), each card's Reaction will only trigger up to two times, to prevent an infinite loop.
A similar form of infinite loop prevention is used for cards with Reactions triggered on an ally's attack, such as Mimik and Puffball. A card with this type of Reaction cannot trigger other cards with the same type of Reaction; otherwise, having two Mimiks in a row would lead to an infinite number of attacks.
If a card would trigger against multiple targets at once (such as if Snoffel Snows the whole field while Kobonker is active), the card triggers against each target in reverse turn order, starting from the back of the field and working towards the front.
Reactions are separate from any non-triggering ability that activates under a specific condition, and those abilities can still activate even if the card is Snowed. For instance, if a card has both the 
Punchfist Charm and 
Tiger Charm attached, it will gain Smackback and "Gain 1 Teeth when hit." However, if this card is File:Snowed.png Snowed and thus cannot trigger via Smackback, it will still gain Teeth when hit by something. If this card becomes Inked, both of these abilities are negated, and it will not react when attacked or gain Teeth when hit.
Almost all Reactions trigger in between Frenzy attacks, so Smackback will interrupt attackers with Frenzy before their Frenzy attacks finish (which may even kill the attacker before they finish their attacks). Similarly, Mimik and Mega Mimik trigger in between hits if the attacking ally in the row has Frenzy. When interrupting Frenzy attacks this way, the reacting card can still use all its own Frenzy; for instance, if Foxee attacks a Warthog that has gained Frenzy via the Wild ability, Foxee will hit the Warthog once, and then the Warthog will react against them with all of its Frenzy (or as much as is needed to kill Foxee). Uniquely, Maw Jaw's Reaction does not trigger until all Frenzy attacks finish, after which it will trigger multiple times in a row (once for each time it was hit). It is not known if this is intended behavior, as all other Reactions interrupt attacks when possible.
Checking if a card's 
Overburn should cause it to explode has higher priority than checking its Reaction. If a card would react to something that also causes its health to be lower than its Overburn (whether by inflicting Overburn or damaging it), it will explode before it gets the chance to react. If the card survives its own explosion with 
Shell, 
Block, or Scrap, it will react after the explosion.
Resolving a card's ability or effect is also higher-priority than checking Reactions, so a card will not attempt to react until all the card's effects are applied. For instance, if Maw Jaw is hit by the Berry Blade, which deals damage and then heals the front ally, Maw Jaw will not react until the ally is healed. Similarly, if Monch eats an ally while Groff is on the field, Groff will not react until Monch has finished attacking. This property is also what prevents cards from reacting to hits that inflict them with Snow or Ink.
Reactions have a hidden internal order of operations that is not immediately obvious, mainly because some Reactions are triggered on attack declaration, while others are triggered on hit. For instance, assume that a Companion has a Mimik in the row and then attacks an enemy with Smackback. Mimik triggers whenever an ally in the row attacks, while Smackback triggers when the card is hit by another. Because an ally declaring an attack is an earlier event than actually hitting the card, the Companion would attack and hit the enemy card, and then Mimik would trigger and attack before the enemy card could react. If the enemy survived both of these attacks, it would then appropriately trigger against the Companion and Mimik.
Other Languages
| Language | Official Name |
|---|---|
| Chinese (Simplified) |
反应 Fǎn yìng |
| Chinese (Traditional) |
反應 Fǎn yīng |
| Korean | 반응 Baneung |
| Japanese | リアクション Riakushon |
Cards and effects that interact with Reactions
| Player cards with Reactions | Player effects that interact with Reactions | Enemy cards with Reactions |
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