When Mjölnir enters the battlefield, attach it to target legendary creature you control. Whenever equipped creature attacks, tap target creature defending player controls and put a stun counter (If a permanent with a stun counter would become untapped, remove one from it instead.) on it. Then Mjölnir deals damage to each opponent equal to the number of tapped creatures that opponent controls. Equip (: Attach to target creature you control. Equip only as a sorcery. This card enters the battlefield unattached and stays on the battlefield if the creature leaves.)