In episode 29 (season 2, episode 12), Howard (not included in the set) built a killer robot for him, Sheldon, Leonard and Raj to use in a killer robot tournament. But as Penny (also not included) told Howard she found him creepy and pathetic, he got depressed. One day later, Barry Kripke, Sheldon's annoying and arrogant rival, challenged him and the guys to a duel between their robots before the tournament. Though Leonard tried to decline due to Howard (the engineer) being depressed, Sheldon, blinded by his pride and arrogance, accepted. They met in the university's kinetics lab. There, just as the duel began, it turned out that Kripke's Krippler was superior than M.O.N.T.E. (Howard's robot), which was brutally destroyed.