There's No Witch Like an Old Witch Bewitched : Season 1 Episode 27

When a depressed Aunt Clara volunteers to babysit for a friend of Samantha and Darrin's, her magical tricks with toys and games make her a success, and she quickly becomes the most popular caretaker in the neighbourhood. But after she tells her charges that she is a witch, a suspicious mother brings her before a judge for a competency hearing.