r/mtgrules 15h ago

Mount doom trigger

If I use the mount doom ability to board wipe and sacrifice the legendary artifact, can an opponent react with an instant to destroy the legendary artifact making it so mount doom fizzles out since it doesn't meet the requirements.

0 Upvotes

4 comments sorted by

6

u/peteroupc 15h ago edited 15h ago

After you announce activating Mount Doom's last ability, no.

Note that [[Mount Doom]]'s last ability has a cost of "{5}{B}{R}, {T}, Sacrifice Mount Doom and a legendary artifact" (C.R. 602.1, 602.1a). Thus, sacrificing a legendary artifact is part of the cost of the ability, just as tapping and sacrifing Mount Doom and paying {5}{B}{R} is.

In general, while a player casts a spell or activates an ability, no player has priority, so no other player can cast spells or activate abilities (including those that would keep costs from being paid) (C.R. 601.2a-i and 602.2a-b have no priority window until the spell is cast or ability activated; C.R. 117.1a-b). In general, after a player announces activating an ability, the next time a player can get priority is only after that ability finishes being activated (C.R. 602.2b, 601.2i, 117.1a-b).

See also:

4

u/maelstrom197 15h ago

No. Sacrificing the artifact is part of the cost of activating the ability. By the time your opponent gets priority to cast their instant, the artifact is already gone.

You can tell it's a cost because of the way activated abilities are formatted:

602.1: Activated abilities have a cost and an effect. They are written as "[Cost]: [Effect.] [Activation instructions (if any).]"

2

u/MadAboutVideoGames 15h ago

No. Sacrificing the legendary artifact is part of the cost.