Ephemerate + Returned Pastcaller + Time Walk

Ephemerate

Returned Pastcaller

Time Walk

How it works

1. Cast Time Walk by paying its mana cost, causing you to take an extra turn after this one.
2. Cast Ephemerate by paying , blinking Returned Pastcaller and exiling Ephemerate.
3. When Returned Pastcaller enters, it triggers, returning Time Walk from your graveyard to your hand.
4. Move to your next turn. At the beginning of your upkeep, Ephemerate's rebound ability triggers, causing you to cast it from exile without paying its mana cost.
5. Resolve Ephemerate, blinking Returned Pastcaller.
6. When Returned Pastcaller enters, it triggers, returning Ephemerate from your graveyard to your hand.
7. Repeat.