Ichneumon (medieval zoology)

In medieval literature, the ichneumon or echinemon was the enemy of the dragon. When it sees a dragon, the ichneumon covers itself with mud, and closing its nostrils with its tail, attacks and kills the dragon. The ichneumon was also considered by some to be the enemy of the crocodile and the asp, and attack them in the same way. The name was used for the pharaoh's rat, mongoose, or Egyptian mongoose (Herpestes ichneumon), which attacks snakes; it can also mean otter. The ichneumon is shaped similarly to a ferret. Although much slimmer in its shape, and the head is elongated. Also, it is an animal that can move swiftly and is able to jump a couple of yards with a single leap.

Etymology
Ichneumon (ἰχνεύμων) means "tracker" in Greek. Cockatrice, a name for another mythical beast, derives from calcatrix, a Latin translation of "trample" or "(feminine)tread on". The Ichneumon was one of the few who could look at a cockatrice without turning to stone.