Hythonia the Cruel

Deathtouch
{6}{B}{B}: Monstrosity 3. (If this creature isn't monstrous, put three +1/+1 counters on it and it becomes monstrous.)
When Hythonia becomes monstrous, destroy all non-Gorgon creatures.

Come Back Wrong

Destroy target creature. If a creature card is put into a graveyard this way, return it to the battlefield under your control. Sacrifice it at the beginning of your next end step.

Murder

Doom Blade

Swamp

Power Word Kill

Destroy target non-Angel, non-Demon, non-Devil, non-Dragon creature.