is an semi-retired American professional wrestler. He is best known for his stint in the World Wrestling Federation under the ring name Damien Demento.

Professional wrestling career

Early career

After training under Johnny Rodz, Theis made his debut in 1987 under the ring name Jonn Reinhart. He soon renamed himself to Mondo Kleen and began wrestling on the independent circuit. In September 1992 he had a try out match with WCW, wrestling as Mando Phil.

World Wrestling Federation (1992–1993)

After The Bushwhackers helped forward of a tape of Theis performing an interview, the World Wrestling Federation signed him to a contract. Theis, under his Mondo Kleen ring name, debuted in WWF at a live event on October 2, 1992 in a losing effort to Jeff Jarrett. On the October 12 episode of Superstars of Wrestling, Theis made his televised in-ring debut as Damien Demento, a villainous character who hailed from "The Outer Reaches of Your Mind" and showed mentally disturbed behavior. He then proceeded to defeat Steve May in his televised debut match. On the October 28 episode of Wrestling Challenge, he defeated Jim Brunzell.

Demento was in the main event of the debut episode of Monday Night Raw on January 11, 1993, losing to The Undertaker. Demento made his only pay-per-view appearance at Royal Rumble as a participant in the 1993 Royal Rumble match and lasted over twelve minutes before being eliminated by Carlos Colón. After this, Demento competed almost solely on house shows before leaving the WWF in October 1993.

Retirement and return

After a stint on the East Coast independent circuit, Theis retired from wrestling in 1994. Theis, under his Damien Demento ring name, made a short return to wrestling on November 8, 2008, where he defeated The Musketeer in a match for the New York-based World of Unpredictable Wrestling, a month later they had a rematch where Demento was on the losing end.

He made another return to the squared circle in September 24, 2011. This time wrestling as "Mondo Kleen" as he defeated Steven Person in a steel cage match at a show that WUW promoted for the Dumbo Arts Festival.

On October 29, 2011, Damien Demento defeated long time WUW Trophy Champion "Izzy" Israel Joffe at the WUW October show at Gleason's gym to win the WUW Trophy Championship. On December 10, 2011, Israel Joffe defeated Damien Demento at the WUW December show at Gleason's gym.