Night Dealings

Whenever a source you control deals damage to another player, put that many theft counters on this enchantment. {2}{B}{B}, Remove X theft counters from this enchantment: Search your library for a nonland card with mana value X, reveal it, put it into your hand, then shuffle.

From Magic: The Gathering.

Open the interactive version on https://mythscribe.cloud/app/tcg/cards/cms6oblsn7w0ppb1hnv0jd7qy.