Omarthis, Ghostfire Initiate

Legendary Creature — Spirit Snake

Omarthis enters with X +1/+1 counters on it. Whenever you put one or more +1/+1 counters on another colorless creature, you may put a +1/+1 counter on Omarthis. When Omarthis dies, manifest a number of cards from the top of your library equal to the number of counters on it.