Necrotic Bite

Necrotic bite [minor] by Iczer

'hmmm tasty'

The character has a set of 'retractable' fangs that can be used to inflict bite attacks. The character's bite inflicts 2D6 damage (no PS bonus) but has a deleterious secondary effect.
The character's saliva infects the wound, eating flesh progressively. Upon being bitten, the target makes a saving throw vs lethal poison. If successful, he takes one point of damage per level of the biter and that ends the bite. If he fails, he takes the one point per level damage and he takes an extra 2 damage per round for each bite he has failed a saving throw on. He continues to take damage at the start of each melee round for one melee round per level, but each subsequent bite resets the duration. The target of multiple bites (and multiple failed saves) can quickly find himself suffering from deep wounds.
Despite the saving throw, the bites are not poison per se, but rather a flesh eating acid. Immunity or resistance to toxins and poisons do not assist the target, though resistance to acids will. Obviously, targets that are not flesh and blood suffer no damage beyond the initial bite.