Fire Elemental

Fire Elementals hit hard and fast. Be careful or you could be dead before you realize you are seriously hurt. They also do not like to move, preferring to stay at a distance and pummel you with ranged DPS unless you move out of range and force them to come to you. Once they move they will move all the way to melee range.
One more thing... Fire Elemental's Flame attack will set you on fire and make you run randomly, screaming like.... well, like a person on fire. This will tend to run you into more mobs, quickly creating adds.