Chained Throatseeker 
Creature — Phyrexian Horror
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.) This creature can't attack unless defending player is poisoned.
Legality
standardNOT LEGALpioneerNOT LEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL