Mallet

Etymology 1
Derived from the name of the inventor, Swiss engineer.

Noun

 * 1) A type of articulated locomotive, in which there are two powered trucks, with the rear truck being rigidly attached to the main body and boiler of the locomotive, while the front powered truck is attached to the rear by a hinge, so that it may swing from side to side, and with the front end of the boiler resting upon a sliding bearing on the swinging front truck.

Etymology 2
Cryptographic scenarios use archetypal characters with standard names chosen to remember their role: Mallet was derived from "malicious" and "man-in-the-middle attack", as well as the tool.

Proper noun

 * 1)  Often the malicious party in examples of threat scenarios. See.