From Creatures Wikia
The Vicious Norns are a norn breed made by KC11. They are capable of eating critters, and once adolescent, they will react to a creature slapping them by hitting back repeatedly. However, the senile norns die easily if slapped. They use the Bruin Norn sprites and have a dark reddish or pink tint.
Other notes: They have an interesting mating dance, and the adolesents do not take kindly to being pushed.
Update: KC11 will soon be hosting an updated version of the Vicious norns. These norns will have the CFE updates, as well as a reduced tendency to hunt down their own kind and an increased tendency to hunt down grendels, ettins, and norns of other breeds.