All right, hypothetical scenario time.
My opponent has a Restored Gengar as his Active Pokemon and he's got a Snowpoint Temple in play to boot. So he's got 130 HP.
I, on the other hand, have a Belted Steelix as my Active and at full power. I Gaia Crush his Gengar for 120 damage, and opt to destroy his Snowpoint Temple.
So the question is: does my opponent get to flip for Fainting Spell, or not?
My opponent has a Restored Gengar as his Active Pokemon and he's got a Snowpoint Temple in play to boot. So he's got 130 HP.
I, on the other hand, have a Belted Steelix as my Active and at full power. I Gaia Crush his Gengar for 120 damage, and opt to destroy his Snowpoint Temple.
So the question is: does my opponent get to flip for Fainting Spell, or not?