Trigger / Triggered Ability

Trigger / Triggered Ability is an ability that happens automatically when a specific event occurs in the game. You can spot one by its wording: it starts with “when”, “whenever” or “at”, such as “whenever this creature attacks” or “at the beginning of your upkeep”.

Once the event happens, the ability goes onto the stack and resolves like a spell would. You do not choose to activate it, which is the key difference from an ability you pay a cost to use.

How Triggers Work

A trigger has two parts: the condition that sets it off, and the effect that follows. If the condition is met, the ability triggers, even if you would rather it did not.

Some triggers are optional (“you may”), and some ask you to choose a target when they go on the stack. Targets are chosen when the trigger is put on the stack, not when it resolves.

Triggers on MTG Arena vs Paper

Arena tracks every trigger for you, puts it on the stack and pings you if a decision is needed. You can play for months without ever thinking about whether a trigger happened.

In paper, the players are responsible for remembering their own triggers. A missed trigger is a real rules issue, which is why triggered abilities come up so often in tournament etiquette and judge calls.

Common Types of Trigger

Enters the battlefield effects are the best-known case, and you will see them written as ETB. Others fire on attacking, dying, drawing a card, playing a land or the start of a turn.

Learning the trigger words helps you read new cards quickly. If a card says “whenever”, ask yourself what has to happen and how often it can happen in a turn.