Cosmic Sovereign

Flying, Haste {R}: This creature gets +1/+0 until end of turn. At the beginning of combat on your turn, conjure a random creature card with mana value X onto the battlefield, where X is this creature's power. That creature gains haste. Exile it at the beginning of the next end step.

From Magic: The Gathering.

Open the interactive version on https://mythscribe.cloud/app/tcg/cards/cms6o2xy80wo1pb1hujkxrf1e.