Hero's Terrorhorn

Equip {b} Can only equip to a superhero

{b}Tap equipped creature. Choose an opponent.
They get the option to tap all of their creatures.
If a creature isn't tapped or if a creature they control is already tapped, put a -1/-1 counter on that creature.
Though the sound of the horn sends enemies running, it also makes it's blower pee their pants.