Modified Protocol droid
4-LOM's was originally programmed as a service driod on a luxury liner, but after some rogue malfunctioning 4-LOM turned to a life of thievery. Hearing of this, Jabba the Hutt modified 4-LOM further to become a bounty hunting droid which he then teamed up with another bounty hunter named Zuckuss. 4-LOM was one of several bounty hunters hired by Darth Vader to track down the Millennium Falcon. Later after failing to capture Solo, 4-LOM tried to steal the carbonite frozen Solo aboard the Slave 1. Boba Fett put a blaster bolt into his insectoid head.
Trivia: 4-LOM is an acronym (for the love of money).