The Great Gazoo was a little green alien on the syndicated cartoon
The Flintstones. He was short and floated, with a large green helmet with
Martian Antannae, and a green spacesuit with a cape. He also had a sort of proper English voice, though I can't place the accent.
He first appeared in the Flintstones episode 145, "The Great Gazoo" on October 29, 1965. Apparently by that point in the show, the ratings were sagging after four years. He was banished from the planet Zetox, his mission was to serve (or protect) the prehistoric "Dumb-dumbs" Fred and Barney. Only the two could see him, and when they called his name he would appear, hovering over them. People thought they were sneezing when they often called for him. He often would pop up or leave just as suddenly.
Some people liked him, he added some antics to the show. Others thought it was awful, perhaps when the show jumped the shark. (What was an alien doing in a show about a stone-age family?)