Abyss-Skulk Reaper

Abyss-Skulk Reaper enters the battlefield tapped.
Whenever you cast a spell from your graveyard,
you may pay {b}. If you do, return Abyss-Skulk
Reaper from your graveyard to your hand.
The residents of Infernia are always welcoming of
visitors, but one should fear their hospitality.