If my opponent casts Scapeshift sacrificing all their lands (7x) and then finds Valakut and 6 mountains, but let's say one of them is nonbasic (i.e. Stomping Ground) can I respond to the Valakut trigger by destroying the nonbasic mountain with Fulminator Mage? Then there will be less than five "other mountains" when the triggers try to resolve, ultimately negating the pile of lightning bolt effects on the stack?
Valakut has an intervening 'if' clause that states the condition must be true for the ability to trigger and also be true when it resolves. So yes you can indeed use Fulminator Mage to destroy the Stomping Grounds in response to the triggers. If you do that all but one of the triggers from Valakut will no longer be true and those abilities will be removed from the stack. However the trigger from the Stomping Grounds entering the battlefield is still true (meaning there are still 5 other mountains) so you'd still take 3 points of damage from that trigger.
No, you can't sacrifice the Fulminator Mage before the triggers from the mountains go on the stack, but that doesn't mean that the Mage isn't bad tech, because it actually does work pretty well.
Valakut's trigger has an "intervening-"if"" clause, so when each mountain enters the battlefield, it checks for the presence of 5 other mountains when the trigger tries to go on the stack, and again when it resolves. This means that if they Scapeshift for a Valakut and 6 mountains, you can destroy 1 of the mountains with the triggers on the stack. You'll take 3 damage from the mountain you destroyed (the 5 other mountains are still there, after all), but the other 5 mountains will only see 4 other mountains on resolution, so the ability is removed from the stack without resolving, and you take only 3 damage instead of 18.
Alternatively, could I respond in between triggers? For example, in the above scenario, the stomping ground's Valakut trigger must resolve, but let's say I've got a Death's Shadow on board and I'd like to take more than 3 damage. Can I let two of the triggers resolve, hit me (assuming they're targeting me) and then intervene with the Fulminator Mage to negate the remaining four Valakut triggers by ensuring there are not 5 other mountains by the time they try to resolve?
Alternatively, could I respond in between triggers? For example, in the above scenario, the stomping ground's Valakut trigger must resolve, but let's say I've got a Death's Shadow on board and I'd like to take more than 3 damage. Can I let two of the triggers resolve, hit me (assuming they're targeting me) and then intervene with the Fulminator Mage to negate the remaining four Valakut triggers by ensuring there are not 5 other mountains by the time they try to resolve?
You can. The ability is a may ability so the opponent can also choose not to deal damage if they don't want to, but you can activate Fulminator or any other land destruction at any time to reduce them below the necessary mountain count and stop the abilities.
If my opponent casts Scapeshift sacrificing all their lands (7x) and then finds Valakut and 6 mountains, but let's say one of them is nonbasic (i.e. Stomping Ground) can I respond to the Valakut trigger by destroying the nonbasic mountain with Fulminator Mage? Then there will be less than five "other mountains" when the triggers try to resolve, ultimately negating the pile of lightning bolt effects on the stack?
Please advise me on this interaction. Thank you
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Valakut has an intervening 'if' clause that states the condition must be true for the ability to trigger and also be true when it resolves. So yes you can indeed use Fulminator Mage to destroy the Stomping Grounds in response to the triggers. If you do that all but one of the triggers from Valakut will no longer be true and those abilities will be removed from the stack. However the trigger from the Stomping Grounds entering the battlefield is still true (meaning there are still 5 other mountains) so you'd still take 3 points of damage from that trigger.
https://www.mtgsalvation.com/forums/magic-fundamentals/magic-rulings/magic-rulings-archives/536932-valakut-vs-fulminator-mage
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Draft My Cube!
You can. The ability is a may ability so the opponent can also choose not to deal damage if they don't want to, but you can activate Fulminator or any other land destruction at any time to reduce them below the necessary mountain count and stop the abilities.
Draft My Cube!