Impetuous Protege

The attack trigger reads as a punishment clause for the opponent's own offense: the more they commit to attacking, the bigger this body swings back. With a 0/4 base it does nothing while the board is still: the power comes entirely from whatever the opponent has tapped out, which means it scales off their aggression, not yours. That makes it a reactive threat dressed as a creature, rewarding a patient defensive posture where you let the opponent overextend into combat, then crash back with a striker sized to their own largest attacker. The 0/4 frame is what makes the bargain fair: stalled on a quiet board, it is a wall and nothing more, so the bonus only ever materializes when the opponent has chosen to expose creatures by tapping them.

The Partner with line ties it to Proud Mentor, a two-card package built to be found and assembled together rather than drawn at random. The mechanic was the headline of a multiplayer-focused era of design, and Impetuous Protege sits firmly on the combat-math side of its pairing: where its partner leans on the defensive support half, this one is the closer that turns the opponent's tapped board into a number. As a piece of design it is a teaching tool about combat tempo: it asks you to read the board, count tapped power, and pick the turn when swinging back is worth more than holding the line.