Seething Skitter-Priest is a uncommon Creature — Phyrexian Cleric card from Alchemy: Phyrexia (YONE), collector number 27.
Toxic 1 When Seething Skitter-Priest enters, creatures you control and creature cards in your hand perpetually gain "When this creature dies, create a 1/1 colorless Phyrexian Mite artifact creature token with toxic 1 and 'This creature can't block.'"