Anthony Salvatore Casso (May 21, 1942 – December 15, 2020), nicknamed "Gaspipe", was an American mobster and underboss of the Lucchese crime family. During his career in organized crime, he was regarded as a "homicidal maniac" in the Italian-American Mafia. Casso is suspected of having committed dozens of murders, and had confessed to involvement in between 15 and 36 murders.
Government witness Anthony Accetturo, the former caporegime of The Jersey Crew, once said of Casso, "all he wanted to do is kill, kill, get what you can, even if you didn't earn it". In interviews, and on the witness stand, Casso confessed involvement in the murders of Frank DeCicco, Roy DeMeo, and Vladimir Reznikov. Casso also admitted to several attempts to murder Gambino family boss John Gotti.

Following his arrest in 1993, Casso became one of the highest-ranking members of the Mafia to turn informant. After taking a plea agreement, he was placed in the witness protection program, however, in 1998, it was rescinded and Casso was dropped from the program after several infractions. Later that year, a federal judge sentenced him to 455 years in prison for racketeering, extortion, and murder.

Casso died in prison custody from complications related to COVID-19 on December 15, 2020.