Rule 370.1.a

An event is the singular moment that results from a Game Action being performed or from a Game Object changing state. Example: The moment that results from a unit being killed is an event that can be referenced by game effects, or even skipped entirely. Example: The moment that results from a unit becoming Mighty is an event that can be referenced by game effects, or even skipped entirely.

• 370.1.a.1 Modifying or replacing an event is the same as modifying or replacing that Game Action or change in state that…
• 370.1.a.2 An event can occur simultaneously with other events only when those events are all the result of the same Game Action…

Official Core Rules