Joey, The Legion

Mad Grit — Whenever Joey deals combat damage to
a player, untap all attacking creatures and after this
phase, there is an additional combat phase. This ability triggers only once each turn.
Feral Frenzy — {1}{b}, {t}: Target creature gets a
Deep Wounds counter. That creature's controller sacrifices it at the beginning of their end step unless
they exert it. Activate only as a sorcery.