Mysterio signed with Lucha Underground on December 12, 2015 and appeared on the second season. On January 10, 2016, Mysterio teamed with Dragon Azteca Jr. and Prince Puma to defeat Ivelisse, Johnny Mundo and Son of Havoc and Fénix, Jack Evans, and PJ Black and Cortez Castro, Joey Ryan and Mr. Cisco in a 4-way Trio Tag Team Elimination Match for the Lucha Underground Trios Championship. Mysterio was the second competitor to enter the second ever Aztec Warfare match and was the final elimination by the eventual winner Matanza. On January 31, 2016, at Ultima Lucha Dos, Rey Mysterio defeated Prince Puma in a singles match. Mysterio defeated Chavo Guerrero Jr. in a Loser Leaves Match. On April 9, 2016 Mysterio was in an Aztec Warfare match where he eliminated Matanza Cueto after Mysterio was eliminated by Johnny Mundo.