Impetuous Protege

Partner with Proud Mentor (When this creature enters, target player may put Proud Mentor into their hand from their library, then shuffle.) Whenever this creature attacks, it gets +X/+0 until end of turn, where X is the greatest power among tapped creatures your opponents control.

From Magic: The Gathering.

Open the interactive version on https://mythscribe.cloud/app/tcg/cards/cms6o7zxo50b7pb1hofe7k438.