Ricardo Amezquita Carreño (born December 9, 1968), better known by his ring name Virus, is a Mexican luchador (or professional wrestler). He is working for Consejo Mundial de Lucha Libre (CMLL), and portrays a rudo ("Bad guy") wrestling character. Amezquita originally worked in CMLL's Minis division as Piratita Morgan, and held the CMLL World Mini-Estrella Championship under the name Damiancito El Guerrero, but was later moved into the regular division and given the name "Virus". He has served as one of the main trainers for CMLL's wrestling school, having had a hand in training hundreds of students at the CMLL school since 2008 either to some degree.

As Virus, Amezquita has held the CMLL Japan Super Lightweight Championship, CMLL World Super Lightweight Championship and the Mexican National Lightweight Championship as well as winning CMLL's annual Reyes del Aire tournament in 2007. In the Mini-Estrellas division he won the CMLL World Mini-Estrella Championship. He is currently the leader of Los Cancerberos del Infierno, a stable consisting of himself and Cancerbero.

Ricardo Amezquita made his professional wrestling debut on April 20, 1986, under the ring name "Bird Boy", an enmascarado (or masked wrestler) with a bird inspired ring persona. He briefly teamed with Bird Boy II, but because of his small size he mainly worked on the low end of the card in the Universal Wrestling Association promotion. On July 27, 1991, Bird Boy defeated Super Archie to win the UWA World Featherweight Championship, as a part of a storyline feud between the two. The storyline culminated in Bird Boy defeating Super Archie in a Lucha de Apuestas, or "bet match", after which Super Archie had to remove his mask. As Bird Boy, he held the Featherweight title for over a year, losing it on August 25, 1992, to El Coralillo.

Amezquita had already begun working with Consejo Mundial de Lucha Libre (CMLL) before he lost the UWA World Featherweight Championship, and became CMLL Exclusive after dropping the title. in 1992 then-CMLL booker Antonio Peña left CMLL to form his own promotion, Asistencia Asesoría y Administración (AAA); Peña had been the mastermind behind the CMLL Minis division and most of the Minis in CMLL decided to leave with Peña. Amezquita and a number of other wrestlers were brought in to replenish the division. Working in the Mini division does not mean that Amezquita has dwarfism, it is not uncommon for very short wrestlers to work in the "Mini" division in Mexico. Ricardo Amezquita was one of the wrestlers brought into CMLL to replenish the division after losing most of their workers and was given the ring persona of Piratita Morgan, a mini version of Pirata Morgan who worked in CMLL at the time and replaced the original Piratita Morgan that had left CMLL to join AAA. He often accompanied members of Los Bucaneros (Pirata Morgan and Rey Bucanero) to the ring, and would interfere on their behalf. Due to CMLL's policy of not having regular sized and Mini-Estrellas compete in the same match Piratita Morgan never officially teamed up with the rest of the "Bucaneros". In 1994 Pirata Morgan left CMLL to join AAA as well, negating the need to have the smaller version of the character working for CMLL.

While trying to figure out a new ring character, Amezquita was offered the name "Damiancito El Guerrero" by Alfonso Lira, who worked as Damian El Guerrero at that time. He worked his first match under that name on November 6, 1994, when he and Ultratumbita lost to Orito and Ultimo Dragoncito. When he became Damiancito, Amezquita began working unmasked without losing a Lucha de Apuestas match. In 1995, Amezquita toured Japan and worked for the W*ING promotion where he was billed simply as "Damiancito", a mini version of Damián 666 who worked for W*ING at the time. Subsequently he has mistakenly been described as working as "Damiancito" or "Damiancto 666" in CMLL as well, but it was only in Japan that he worked as a mini of Damián 666 and is not related to Pequeño Damián 666.

After returning from Japan Damiancito El Guerrero defeated Máscarita Mágica to win the CMLL World Mini-Estrella Championship on February 27, 1996. The storyline between the two Mini-Estrellas later led to Damiancito defeating Mascarita Mágica in a Lucha de Apuestas bet match, where Mascarita Mágica was forced to have all his hair shaved off as a result of losing the match. In late 1997 CMLL booked an eight-man elimination match where the winner would earn the right to tag team with "regular sized" wrestlers. Damiancito El Guerrero defeated Cicloncito Ramírez, Tritoncito, Pequeño Cochisse, Platita, Guerrerito del Future, Pequeño Sayama an Fierito to earn the right to work with "regular sized" wrestlers.

In early 1998 he made his debut as part of the regular-sized division under the name "Virus", no mention was made that Virus used to work as Damiancito El Guerrero or that he still held the CMLL World Mini-Estrella Championship. On May 7, 1998, Virus defeated El Oriental to win the vacant Mexican National Lightweight Championship, a title CMLL had brought back to help showcase smaller workers such as Virus. After winning the title Virus worked a storyline feud against El Oriental, centering on Virus' Mexican Lightweight title and Orientál's Districto Federatl Lightweight title. Despite several title matches neither belt changed hands during the course of the storyline. By 1999, CMLL decided that it was time to crown a new World Mini-Estrella Champion, as Virus was still technically the champion despite not having worked as a mini for more than a year. Instead of making Virus return to the Minis division to lose the title, CMLL decided to give the championship to Ultimo Dragoncito and subsequently announce that Ultimo Dragoncito had "won" the title on an undisclosed day in October 1999. In 1999 and 2000, CMLL made several tours of Japan to establish a 'CMLL Japan' branch; Virus was one of the workers who regularly toured Japan and would capture the CMLL Japan Super Lightweight Championship on November 25, 1999. On August 6, 2000 Virus lost the CMLL Japan Super Lightweight title to Ricky Marvin and then on November 29, 2000 also lost the Mexican National Lightweight title to Ricky Marvin. Virus continued to show that while he may not have the size to be a headliner he had a knack for helping young wrestlers improve by working with them in the ring.

On August 21, 2001 Virus participated in his first major CMLL tournament, the Torneo Gran Alternativa ("Great Alternative Tournament") where he was teamed up with Blue Panther. In the first round they defeated the team of Alan Stone and Mr. Niebla but lost to Olímpico and Sicodelico Jr., who would go on to win the entire tournament. After having been a Rudo (a Heel, or bad guy) his entire career Virus was turned Tecnico (Face or good guy) in 2002. In 2003 he took part in a series of matches between CMLL tecnicos, himself, Ricky Marvin and Volador Jr., and a group called "the Havana Brothers" based out of southern California that consisted of Rocky Romero, Ricky Reyes and T. J. Perkins). The well received series of matches between the six led CMLL to create the CMLL World Super Lightweight Championship. Rocky Romero became the first champion but lost the title to Virus on November 14, 2003. Virus held the title for 392 days before losing it back to Rocky Romero. In 2005 Virus was turned Rudo once more and generally used to help young, high-flying tecnicos get more experience. Over the summer of 2006 Virus represented CMLL in All Japan Pro Wrestling's Junior Heavyweight League tournament. He ended up winning only one match, defeating MAZADA but lost to Katsuhiko Nakajima and Katsushi Takemura, failing to advance in the tournament. On October 2, 2007 Virus won CMLL's recurring Reyes del Aire ("Kings of the Air") tournament outlasting 11 other competitors in a torneo cibernetico, lastly eliminating Valiente to win the match.