Prerequisites
- Changeling Berserker in hand or on the battlefield or in exile
- Changeling Titan in hand or on the battlefield or in exile
- Changeling Hero in hand or on the battlefield or in exile
plus the mana cost of the creature in your hand available
Steps
- Cast Changeling Berserker for its mana cost
- When Changeling Berserker enters, it exiles Changeling Titan until Changeling Berserker leaves the battlefield
- Resolve any additional effects of Changeling Berserker's ETB
- When Changeling Titan leaves the battlefield, Changeling Hero is returned from exile to the battlefield
- When Changeling Hero enters, it exiles Changeling Berserker until Changeling Hero leaves the battlefield
- Resolve any additional effects of Changeling Hero's ETB
- When Changeling Berserker leaves the battlefield, Changeling Titan is returned from exile to the battlefield
- When Changeling Titan enters, it exiles Changeling Hero until Changeling Titan leaves the battlefield
- Resolve any additional effects of Changeling Titan's ETB
- When Changeling Hero leaves the battlefield, Changeling Berserker is returned from exile to the battlefield
- Repeat from step 2
Results
Required Cards 3

Changeling Berserker
Creature — Shapeshifter

Changeling Titan
Creature — Shapeshifter

Changeling Hero
Creature — Shapeshifter