Stormbreaker

Equipped creature gets +10/+10 and loses flying.
Equip {8} ({8}: Attach to target creature
you control. Equip only as a sorcery.)
"It's a mold. A king's weapon. Meant to be the
greatest in Asgard. In theory, it could even
summon the Bifrost."
"Did it have a name?"
"Stormbreaker."
Based on: Colossus Hammer