Septic Rats

Oracle Text

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Whenever Septic Rats attacks, if defending player is poisoned, it gets +1/+1 until end of turn.

Card Rulings

6/1/2011 A player is poisoned if that player has one or more poison counters.
6/1/2011 Septic Rats gets a maximum of +1/+1 from its ability, no matter how many poison counters the defending player has.