Children's TV show from the 70's or did I dream this?

A children's TV show I recall probably sometime between 1973-1978 or so used to give me nightmares.I have since mentioned this to a handful of other people, but no one has a clue what I am talking about. I don't think I made this up but I may not be remembering things entirely correctly.This show, or possibly a segment of a larger show, probably was on Saturday mornings with the other network tv kid shows. The opening showed a boy (real boy, not animated) with a magician's top hat that he set down and it grew into huge proportions. Then, he fell down inside the now gigantic hat. Inside were creatures that reached for him as he fell. He ended up in a land of creatures that all looked like hats, for instance, a nurse's hat, and I think the main plot of the show was how he was going to get home. I think the hat creatures and any other creatures were some sort of muppet/puppet thing.Something about this was profoundly disturbing to my little kid mind, though I don't think it was intended to be scary. Perhaps it was the thought that he could end up in this strange world with no way to get home.With all the info now out in Wikipedia and such I feel like if this show really existed and I didn't dream it, I could find it if only I knew what to search on. I thought that perhaps it was part of a larger show, like the Krofft Supershow, but didn't find it there. I recall another similar show (or shows) that featured Sigmund the Seamonster, and a segment involving two funny androids (one played by a familiar female comedian whose name I don't recall). I don't think that this hat scenario fit into any of these but couldn't swear to it.Does this ring a bell to anyone of a similar age?ETA: The show was Lidsville, as confirmed by pantlessjohnny. Thanks, Pantless! I had the right instinct associating it with the Kroffts. It ran earlier than I thought, from 1971-1973, which means I would have been between the ages of 3 and 5. No wonder all I can remember are a few weird images.