Title for 80's fantasy movie with magic slide
Hi.
I recently had a memory about a fantasy movie that I saw in the early nineties, but I'm assuming it was older than that, probably from the eighties.
All I remember is a boy and girl, brother and sister I think, end up in this magical land with all these strange people and this couple who may have been the king and queen want to adopt these kids. But in order for the kids to become permanent citizens of this land, they have to go down this weird slide. I think anybody who goes down this slide comes out covered in goop, and maybe brainwashed too. After the kids see this, they don't want to stay there anymore. The kids may or may not have traveled through a forest to get to the magical land.
I'm pretty sure it's a memory of a movie. Any suggestions would be appreciated.
Thanks.
