Barney Feffer claimed to be a security guard at American University. He had a grudge against his former college room mate, Henry Parker and attempted to kill him during the dedication ceremony of a library named in his honor. He encountered K.C., but fooled her into thinking he was a bumbling inept, but earnest do-gooder. Eventually, K.C. figured it out and thwarted his plans, and Barney was arrested after losing a showdown with K.C.
He was portrayed by French Stewart.
- Twin It to Win It (first and only appearance; main antagonist)