Mjölnir, Storm Hammer is a rare Legendary Artifact — Equipment card from Secret Lair Countdown (SLC), collector number 62.
When Mjölnir enters, attach it to target legendary creature you control. Whenever equipped creature attacks, tap target creature defending player controls and put a stun counter on it. Then Mjölnir deals damage to each opponent equal to the number of tapped creatures that opponent controls. Equip {4}