Frostmourne

When Frostmourne enters the battlefield, attach
it to a creature you control, then exile all cards
from all opponents' graveyards.
Equipped creature gets +6/+6 and has Menace.
Whenever equipped creature deals combat
damage to a player, you may cast any number of creature spells from among cards exiled with Frostmourne with total mana value less than
or equal to that damage without paying their
mana costs.
Equip {6}