Your search for "Skull Prophet 304" revealed the following:
Skull Prophet (TDC) from Tarkir: Dragonstorm Commander, available at 401 Games Canada. Rarity: Uncommon Finish: Normal Artist: Nils Hamm Card Text:T: Add B or G.T: Mill two cards. (Put the top two cards of your library into your graveyard.)
Skull Prophet (IKO) from Ikoria: Lair of Behemoths, available at 401 Games Canada. Rarity: Uncommon Finish: Normal Artist: Nils Hamm Card Text:T: Add B or G.T: Put the top two cards of your library into your graveyard.
Skull Prophet (Foil) (IKO) from Ikoria: Lair of Behemoths, available at 401 Games Canada. Rarity: Uncommon Finish: Foil Artist: Nils Hamm Card Text:T: Add B or G.T: Put the top two cards of your library into your graveyard.