Be Cool, Scooby-Doo! (2015)

Season 2: Episode 1

While trick-or-treating with his cousin Scott and a friend when he was little, Fred has a scarring experience when he is ambushed by an evil witch near an abandoned cabin. Several years later, Fred and the gang run into the very same witch on Halloween night in another town. As the gang attempts to solve the mystery of the witch, they must also convince Fred that he is incorrect in his belief that a mystery cannot be solved on Halloween night.