Sean Michael Waltman (born July 13, 1972) is an American professional wrestler. He wrestled for the World Wrestling Federation (WWF, now called WWE) under the ring names 1–2–3 Kid and X-Pac intermittently between 1993 and 2002, World Championship Wrestling (WCW) as Syxx, and Total Nonstop Action Wrestling (TNA) as Syxx-Pac and Sean Waltman.

He is signed with WWE working in their Legends program. Waltman has won a dozen championships between WWE, WCW, and TNA; the majority were cruiserweight and tag team titles. He is the only wrestler to have held the TNA X Division Championship, the WCW Cruiserweight Championship and the WWF Light Heavyweight Championship; he also held the WCW Cruiserweight and WWF Light Heavyweight titles simultaneously. He was also the final WWF Light Heavyweight Champion before the title was retired in favor of the Cruiserweight Championship he simultaneously held.

He was part of The Kliq, a group of wrestlers known for their influence on WWF storylines in the mid-1990s.