Herry Monster is a big, unibrowed, furry light-blue monster who doesn't know his own strength. His voice is a parody of Jimmy Durante's. In books he is always illustrated as wearing pants with vertical stripes. Herry appeared on the show from 1970 to 2003; in 2004 he appeared in only the debut episode for Season 35 (episode 4057). Herry Monster's birthday is August 31. His best friend is Grover.

He is covered with blue fur, has big black eyebrows, and a long purple nose.