Nascent Metamorph

Whenever this creature attacks or blocks, target opponent reveals cards from the top of their library until they reveal a creature card. This creature becomes a copy of that card until end of turn. Then that player puts all cards revealed this way on the bottom of their library in a random order.

From Magic: The Gathering.

Open the interactive version on https://mythscribe.cloud/app/tcg/cards/cms6ocfki8l4vpb1hjkn6ecl6.