Monk Gyatso + Semblance Anvil + Umbral Mantle

Monk Gyatso

Semblance Anvil

Umbral Mantle

How it works

1. Activate Umbral Mantle's equip ability by paying 0, targeting another nontoken creature you control.
2. Monk Gyatso triggers, airbending the targeted creature.
3. The Umbral Mantle ability fizzles due to no longer having a legal target.
4. Cast the creature from exile by paying 0 due to Semblance Anvil.
5. Repeat.