Level 13 DiseaseGreater Moon Frenzy

Stage 0: The target recovers from the disease.
Stage 1: Initial Effect: The target takes a -2 penalty to Will.
Stage 2: While bloodied, the target must make a saving throw at the end of each turn. If the saving throw fails, the target makes a melee attack on its next turn against a random target within 5 squares of it. If no targets are within 5 squares, the target does nothing but move in a randomly chosen direction.
Stage 3: Final State: The target attacks the nearest creature in its line of sight. If it cannot see any other creatures, it does nothing but move in a randomly chosen direction.
Check: At the end of each extended rest, the target makes an Endurance check if it is at stage 1 or 2.
13 or lower: The stage of the disease increases by one.
14-19: No Change
20 or higher: The stage of the disease decreases by one.

Published in Monster Manual 2, page(s) 160, Dungeon Magazine 197.