Siege Striker

Double strike (This creature deals both first-strike and regular combat damage.) Whenever this creature attacks, you may tap any number of untapped creatures you control. This creature gets +1/+1 until end of turn for each creature tapped this way.

From Magic: The Gathering.

Open the interactive version on https://mythscribe.cloud/app/tcg/cards/cms6oenjiaf11pb1hf9yt7n8z.