Omarthis, Ghostfire Initiate

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.

From Magic: The Gathering.

Open the interactive version on https://mythscribe.cloud/app/tcg/cards/cms6ohmgyco8jpb1h82rcxhl2.