From The Grindhouse Cinema Database
Seymour aka Sinister Seymour (played by Larry Vincent, June 14, 1924—March 9, 1975) was an American television horror host, famed for his character "Seymour," who presented—and heckled—low-budget horror and science fiction movies on Fright Night on KHJ-TV and Seymour's Monster Rally on KTLA, both local stations in Los Angeles between 1969 and 1974. He was noted for his style of criticizing the movies he presented in an offbeat and funny manner, usually appearing in a small window which would pop up in the corner, tossing a quip, then vanishing again. Sometimes he would, using blue-screen, appear in the middle of the movie, apparently interacting with the characters in the movie.
Born in Massachusetts, Vincent was to star in several episodes of The New Three Stooges in 1965. He also had small roles on Get Smart, Mission: Impossible, The Flying Nun, and I Dream of Jeannie.
But before moving to Los Angeles, California, he was "Captain Starr" on WFBM in Indianapolis in the 1960s, as one of a trio of hosts, along with Harlow Hickenlooper and Curley Myers for children's programing, which showed the old Three Stooges shorts, as well as skits for an in-studio audience of children which usually ended up with pie-in-the face comedy and songs from the hosts. In 1968, he became staff director for KHJ-TV.
From 1969 to 1974 Vincent was the host for the horror shows Fright Night on KHJ-TV and Seymour's Monster Rally on KTLA.