Appa, Steadfast Guardian + Planar Gate + Aang, Airbending Master

Appa, Steadfast Guardian

Planar Gate

Aang, Airbending Master

How it works

1. Cast Appa either from your hand or from the command zone by paying plus commander tax if applicable.
2. When Appa enters, it triggers, airbending Aang.
3. Cast Aang from exile by paying 0.
4. Appa triggers, creating a 1/1 Ally creature token.
5. When Aang enters, it triggers, airbending Appa.
6. Cast Appa from exile by paying 0.
7. Repeat from step 2.

This infinite loop relies on a clever cost-reduction setup and a perpetual cycle of exile and re-casting. Planar Gate is the engine that makes the loop free, reducing the cost to recast Appa, Steadfast Guardian and Aang, Airbending Master from exile down to zero. Appa enters the battlefield to airbend Aang, while Aang returns the favor by airbending Appa whenever he enters, creating an endless ping-pong of leaves-the-battlefield and entry triggers. Meanwhile, Appa's second ability converts every spell cast from exile into a growing horde of 1/1 white Ally creature tokens, while Aang quietly racks up experience counters to reward your perpetual motion machine.