vermivex

This creature is created by an unclean spirit possessing a black ram which becomes warped and riddled with worms that cause sickness.  Some evil powers create vermivex by clerical ritual.

Number: 1 (1d4)
Alignment: Neutral
Movement: 120' (40')
Armor Class: 8
Hit Dice: 2d8+2
Attacks: 1 headbutt
Damage: 2d4 + worms
Save: Cleric 1
Morale: 9
Hoard Class: None

This mangy black ram stands 4' at the shoulder and is visibly afflicted by parasites and disease.  It attacks by butting with it's horns.  On a natural 20, one of the worms infesting it will burrow into an open wound or orifice of it's victim.  This leads to nausea (-2 to AC, hit and damage) and loss of 1 point of Constitution every day until either the victim dies or the disease is cured.  A cure disease spell removes the infestation and can kill a vermivex instantly if it fails a save vs. spell.