Golem of Contracts

When you cast this Enchantment choose one
Artfact, Enchantment, Creature
Contract: pay {1} for each card of the chosen type
under your controll
At the Start of combat Golem of Contract may
becomes a 7/7 golem creature with trample and
hexproof until the end of combat.
Golem of Contracts can only attack player that broke
his contract.