Scrappy-Doo was a very energetic and often annoying character. He was initially popular but later became a target of criticism from fans who felt his presence detracted from the original Scooby-Doo formula.
He appeared in several spin-offs and even got his own series, but he was eventually phased out of the main Scooby-Doo shows.
However, he still makes occasional appearances in later series and movies, often with a more toned-down personality.