Cavalier of Dawn + Infinite Reflection + Chamber Sentry

Cavalier of Dawn

Infinite Reflection

Chamber Sentry

How it works

1. Cast Chamber Sentry by paying 0.
2. Chamber Sentry enters the battlefield as a copy of Cavalier of Dawn.
3. Copy of Cavalier of Dawn enter-the-battlefield ability triggers, destroying itself and creating you a 3/3 Golem token.
4. Copy of Cavalier of Dawn dies, triggering itself, returning Chamber Sentry from your graveyard to your hand.
5. Repeat.