Let's say I use Doom Desire with my favorite Choice Specs Jirachi. My opponent really has nothing to do but switch out to his Gengar. I then switch out to my awesome Vaporeon, but as Doom Desire hits (and yes I skipped a turn, deal with it), his Gengar uses Destiny Bomd. What happens? Will it fail? Will it kill Vaporeon and Gengar? Or will it kill Jirachi and Gengar?