Adarkar Valkyrie | Thornbite Staff | Carrion Feeder

Cards

All permanents on the battlefield (
Thornbite Staff attached to
Adarkar Valkyrie).
Adarkar Valkyrie does not have summoning sickness.

Activate
Adarkar Valkyrie by tapping it, targeting
Carrion Feeder.
Activate
Carrion Feeder by sacrificing it.
When
Carrion Feeder dies,
Adarkar Valkyrie triggers twice.
Resolve the first trigger, untapping
Adarkar Valkyrie.
Resolve the second trigger, returning
Carrion Feeder from your graveyard to the battlefield.
Resolve the
Carrion Feeder ability.
Repeat.

You may instead target another nontoken creature you control to get infinite +1/+1 counters on
Carrion Feeder.