I really hate to bump such an old thread, but in my defense, it's a useful thread. I read this back when it was first made, but unfortunately I didn't have an account yet.
Anyway, this is vague. Really vague. But it's been bothering me for years. When I was a kid we had a bunch of blank VHS tapes of random shows, movies, cartoons that my family had recorded over the years. Anyway, one in particular sticks with me, and I have no idea what it was called.
I'm not sure if it was a series or a movie, but it was animated and from what I recall had an 80s kind of style, though it could have been the 70s. The main characters were a couple of kids. I remember there was a baby and at least one boy and one girl. They're in their back yard, and I think their mom complains about laundry disappearing or something. They see a smurf-like creature taking something and they follow him into a cave/portal or something. This leads them to the civilization of the creatures, which had a goofy name like "golly-wogs" or "wally-gogs" or something like that. I remember the baby gets lost and there's a really ominous shot of a tunnel where they think it went. I don't remember much after that, but it ends with the kid's leaving and their mom talks to them, while one of the creatures steals something behind her.
That's all I can remember, and it's been bugging me for a very long time. Somebody please ease my pain.