Dream Halls + Sandstorm Eidolon + Sparkcaster

Dream Halls

Sandstorm Eidolon

Sparkcaster

How it works

1. Cast Sparkcaster by discarding Sandstorm Eidolon.
2. Sandstorm Eidolon triggers from your graveyard, returning from your graveyard to your hand.
3. Sparkcaster enters the battlefield, triggering twice.
4. Resolve the first Sparkcaster trigger, dealing 1 damage to target player or planeswalker.
5. Resolve the second Sparkcaster trigger, returning Sparkcaster from the battlefield to your hand.
6. Repeat.