Mysterio feuded with Juventud Guerrera. Mysterio's uncle Misterio Sr. also took on Guerrera in a tag match: Misterio Sr. and Mysterio Jr. facing Guerrera and his father Fuerza Guerrera. Extreme Championship Wrestling (1995–1996) Mysterio signed with Paul Heyman's Extreme Championship Wrestling (ECW) in 1995. He debuted in September 1995 at Gangstas Paradise, defeating Psicosis, who was also making his ECW debut. A feud between the two began, which included a two out of three falls match and a Mexican Death match. Mysterio also had a series of matches with ECW-newcomer Juventud Guerrera during early 1996. He wrestled his final bout for ECW at Big Ass Extreme Bash in March 1996. World Championship Wrestling Cruiserweight division (1996–1998) Mysterio made his World Championship Wrestling (WCW) debut on June 16, 1996, at The Great American Bash, challenging Dean Malenko for the WCW Cruiserweight Championship in a losing effort. At Bash at the Beach on July 7, he defeated Psicosis in a #1 contender's match to earn another opportunity at the Cruiserweight title. The next night, on the July 8 episode of WCW Monday Nitro, he defeated Malenko to win his first Cruiserweight Championship. He reigned as champion for three months, which included title defenses against the likes of Ultimate Dragon at Hog Wild on August 10, Malenko, and Super Caló at Fall Brawl on September 15 before he lost the title to Malenko at Halloween Havoc on October 27. Mysterio challenged Ultimate Dragon for the J-Crown Championship in a losing effort at World War 3 on November 24. In early 1997, he began a feud with Prince Iaukea over the WCW World Television Championship, culminating in a title match against Iaukea at SuperBrawl VII on February 23, which he lost after Lord Steven Regal attacked him. Mysterio also lost a title rematch at Uncensored on March 16. He defeated Ultimate Dragon at Spring Stampede on April 6, and Yuji Yasuraoka at Slamboree on May 18. Mysterio began a feud with the New World Order (nWo), which culminated when he lost a Mexican Death match to nWo member Konnan at Road Wild on August 9. Mysterio was then involved in a feud with his real-life friend and Cruiserweight Champion Eddie Guerrero, whom he defeated in a Title vs. Mask match at Halloween Havoc on October 26 to win the Cruiserweight Championship for the second time. On the November 10 episode of Nitro, he lost