Acid Cube

When Acid Cube enters the battlefield, it deals
damage equal to its power to target creature.
When Acid Cube deals damage to a creature,
exile all permanents that are attached to that
creature. When Acid Cube is dealt damage by a
creature, it deals damage equal to its power to
that creature.
Creatures fighting against Acid Cube gain
first strike until end of turn. If a permanent
would be attached to Acid Cube, exile that
permanent instead.