Blizzard Troll

Blizzard Troll are blue colored trolls of cold and ice found as allies of the evil Ice Elemental Prince Cryonax, encountered as part of the final battle with Amelyssan in Chapter 10 in the Throne of Bhaal.
When they are brought near to death (a minimum of 1 hit point) they fall unconscious to the ground. They can be killed permanently in that state, but only by acid or fire damage, and if not done quickly, they recover heath and consciousness.
The Blizzard Troll has very rapid regeneration ability at a rate of 6 HP/second. It's melee attack weapon slashes, and applies a damage as well as a potential Stun and Dexterity drain effect. A Saving throw vs. Breath Attack with a -2 penalty can half the cold damage and negate the Stun and attribute drain.