Reveillark | Body Double | Yahenni, Undying Partisan

Cards

Reveillark in your graveyard.
Body Double and
Yahenni on the battlefield (
Body Double as a copy of
Reveillark).

Activate
Yahenni, Undying Partisan by sacrificing
Body Double.
When
Body Double leaves the battlefield, it triggers its
Reveillark ability, returning itself from your graveyard to the battlefield as a copy of
Reveillark.
Resolve the
Yahenni, Undying Partisan ability.
Repeat.