This delightful loop turns a modest common and an uncommon enchantment into a self-sustaining engine of perpetual motion. By using Phyrexian Altar to sacrifice Iridescent Drake, you send the creature to the graveyard while netting a mana of any color. That sacrifice immediately rouses Kaya's Ghostform from the graveyard to rescue its bearer, slipping the Drake right back onto the battlefield. As Iridescent Drake enters, its own trigger reaches into the graveyard to pull Kaya's Ghostform right back with it, re-equipping the cycle and leaving you ready to feed the Altar all over again.