Herigast, Erupting Nullkite + Cloudstone Curio + Molten Echoes

Herigast, Erupting Nullkite

Cloudstone Curio

Molten Echoes

How it works

1. Cast the creature with a generic mana cost by paying its mana cost or emerge cost.
2. When the creature enters the battlefield, Cloudstone Curio and Molten Echoes trigger.
3. Resolve the Cloudstone Curio trigger, choosing to return nothing to your hand.
4. Resolve the Molten Echoes trigger, creating a token copy of the generic mana cost creature.
5. When the creature token enters the battlefield, Cloudstone Curio triggers, returning the nontoken generic mana cost creature from the battlefield to your hand.
6. Cast the generic mana cost creature for its emerge cost by sacrificing the creature token created in step 5, and by paying 0 as the token will have the same mana value.
7. Repeat from step 2.