Brian Alexander Wecht, also known by his stage and character name Ninja Brian, is an American musician, Internet personality and theoretical physicist. He is best known as a member of comedy musical duo Ninja Sex Party and video game-based comedy music trio Starbomb. He is additionally a member of the affiliated Let's Play webseries Game Grumps, all three alongside Dan Avidan.
Wecht originally worked as a theoretical physicist, and notably held research positions at Harvard University, the Massachusetts Institute of Technology, the Institute for Advanced Study, the University of Michigan, and the Queen Mary University of London. Specialized in particle physics, his work included research on string theory, supersymmetry, and quantum field theory. He retired in 2015, choosing to join Game Grumps while focusing on his musical career. He is also the co-creator of The Story Collider, a science-based story telling podcast recorded in front of a live audience. In Ninja Sex Party, Wecht plays the character of "Ninja Brian", an uncommunicative, homicidal masked ninja, in both live shows and music videos. He performed all instruments on early Ninja Sex Party albums, until Tupper Ware Remix Party started acting as their backing band in 2015. Since May 2018, Wecht also portrays Ninja Brian on his own live comedy show titled Ninja Brian's All-Star Variety Luau Spectacular.