No. appearing: 1-6
Armour class: 4/16
Hit dice: 8
Attacks: 1d8 horn or 1d8 trample
Special attacks: Charge, Explosive Fluid
Special defenses: Magic resistance 30%
The Erumpent is a magical creature that resembles a rhinoceros but is far more deadly. Upon charging, not only will it deal double damage but it will attempt to impale the target with its horn. On a hit, the victim is injected with a dose of Exploding Fluid - save vs. poison or be blown to smithereens. The Exploding Fluid can even cause inanimate objects to detonate, and a sufficiently hard object may damage those nearby with shrapnel (20' radius, 2d6 damage, save vs. breath weapon for half).
An adult Erumpent has enough Exploding Fluid for 2-5 doses, and can regenerate that amount over the course of one day. The fluid can be harvested from the corpse and used to create explosive potions.
The Erumpent's hide is magically resistant to spells and has a 30% chance of negating any magical effect that strikes it. The eyes and mouth of the Erumpent do not possess this quality.
The Erumpent is a herbivore, but an extremely bad-tempered one, which may sometimes attack unprovoked. If more than two are encountered, there is a good chance that some will be children (4HD). The presence of children makes the parents much more likely to charge.
(from Fantastic Beasts and Where to Find Them)