I'm looking for the name of an animated movie form the 80s or 90s... all I can remember is its about a boy who somehow travels to another world and meets a princess. Then he lets out this black goo stuff form a big door. Then he has to save that world from the goo. I do remember this one part when they all float around in these pink and yellow bubbles! Please help its driving me crazy!! :p

Is it Little Nimmo??
That's the only one I can think of, Nimmo opens a door of darkness and it floods the place if I remember right. But I don't know if he was dreaming or what.
That's probably not it, but maybe.

Omg yes thank you so much I love you to death!! :D