The Sesame Street monster with the superhero alter ego Super Grover is Grover.
Grover is a blue, furry Muppet monster known for his enthusiasm, politeness, and comic attempts to solve problems. In his superhero persona, Super Grover wears a helmet and cape and tries to help people, although his plans often go humorously wrong.
The character’s history reaches back to a prototype appearance on The Ed Sullivan Show on December 24, 1967. Grover became more fully established on Sesame Street in the early 1970s. Frank Oz performed him for decades, and Eric Jacobson later became the character’s regular performer.
Super Grover is not a separate monster, although the superhero identity can make the name seem like a different character. Grover has also been adapted under different names internationally; in Spain, for example, Grover is called Coco and Super Grover is known as Super Coco.