You control a permanent that can tap to produce at least ({U} magic symbol) .
Steps
Activate the mana-producing permanent by tapping it, adding ({U} magic symbol) .
Activate
Fatestitcher's unearth ability by paying ({U} magic symbol) , returning it from your graveyard to the battlefield and giving it haste until end of turn.
Activate
Fatestitcher by tapping it, untapping the mana-producing permanent.
Activate
Carrion Feeder by sacrificing
Fatestitcher.
Choose to exile
Fatestitcher using
Void Maw's replacement effect instead of
Fatestitcher's.
Resolve the
Carrion Feeder ability, putting a +1/+1 counter on it.
Activate
Void Maw by putting
Fatestitcher from exile into your graveyard, giving