Lust for War

The cruelty here is that it punishes the act of tapping, then forces the creature into the one situation where tapping is unavoidable. The compulsion clause turns the enchanted creature into a clock pointed at its own controller: it must attack each combat if able, and the moment it taps to do so, the Aura itself deals three damage to that creature's controller. Stuck on an opponent's beater, it converts their offense into a slow burn against their own life total, three at a time, and because the aggression is not optional, they cannot defuse the trigger by simply holding the creature back. Note that the damage comes from the Aura, not the creature, so a body with lifelink or infect contributes nothing to softening or redirecting it.

What gives it teeth beyond the attack step is the breadth of "becomes tapped." It does not care how the creature taps, only that it does: convoke, crewing a Vehicle, paying a tap-cost activated ability, a tap effect from either side of the board. A creature with a strong tap ability becomes a self-inflicted wound, and even tapping the thing yourself fires the three damage at its controller. The enchant target is the design's only real restraint, since this does nothing as a pure removal spell and wants a body the opponent will actually keep around. It belongs to the lineage of taxing red curses rather than clean removal: it does not kill the creature, it makes keeping the creature hurt.