Carrion

As an additional cost to cast this spell, sacrifice a creature.
Create X 0/1 black Insect creature tokens, where X is the sacrificed creature's power.

Ashnod's Altar

Su-Chi

Purgatory

Whenever a nontoken creature is put into your graveyard from the battlefield, exile that card.
At the beginning of your upkeep, you may pay {4} and 2 life. If you do, return a card exiled with Purgatory to the battlefield.

Triskelion

Triskelion enters with three +1/+1 counters on it.
Remove a +1/+1 counter from Triskelion: It deals 1 damage to any target.