Plutis, God of Tithes

Deathtouch, indestructible
As long as you control three or less treasures, Plutis, God of Tithes isn't a creature.
Whenever an opponent casts a spell, they may sacrifice a permanent. If the player doesn't, you create a Treasure token. (It's an artifact with {t}, Sacrifice this artifact: Add one mana of any color.)