Lasher's Vault

{t}: Add {g} to your mana pool.

At the beginning of your upkeep, if you control
Agony's Vault, Lasher's Vault, Phage's Vault, and
Riot's Vault, exile them and create Hybrid, a
legendary 12/12 colorless Symbiote creature with
Menace, Trample, Haste, and Lifelink and "When
this creature dies, create four 3/3 colorless Symbiote creature tokens"

They're becoming some kind of Hybrid! - Zwerling