Koopa, the Continental Shell

Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)
Hexproof, indestructible
Koopa, the Continental Shell can't attack or block unless you have the city's blessing.
At the beginning of your end step, create two colorless Treasure artifact tokens with
"{t}, Sacrifice this artifact: Add one mana of any color."