On the January 15, 1998, episode of "WCW Thunder", Mysterio defeated Juventud to win his third Cruiserweight Championship, but lost it nine days later to Chris Jericho at Souled Out. After the match, Jericho continued the beating by using a toolbox he found at ringside. This storyline was used to cover Mysterio's need for a knee operation that kept him out of the ring for six months. He made his return at Bash at the Beach, where he defeated Jericho for his fourth Cruiserweight championship. The next night, however, the result was overturned and the belt returned to Jericho due to Dean Malenko interfering. Later that year, Eddie Guerrero formed a Mexican stable known as the "Latino World Order" (LWO) (a spin off of New World Order) that included nearly every luchador in the promotion. Mysterio continually refused to join and feuded with Guerrero and the LWO members, including winning a match against longtime rival and LWO member Psicosis in a match at Road Wild. He was finally forced to join the group after losing a match to Eddie Guerrero. Mysterio's on-and-off tag team partner Billy Kidman joined him during the feud with LWO, wrestling against the LWO despite Mysterio being a part of the group. His alliance with Kidman was formed after Mysterio helped Kidman defeat Juventud for the Cruiserweight Championship at World War 3. Mysterio went up against Kidman for the title at Starrcade but was unsuccessful winning back the title in a triangle match that also involved Juventud. Kidman once again defeated Mysterio for the title at Souled Out in a fatal four-way match that also included Psicosis and Juventud.