Ok, tonight my girlfriend asked me if I remembered an animated movie that had a little mouse running from this black sludge (she thinks it might have been tar)(but it was the villain of the movie) and it also involved a locked door.

I know its not much to work with, but if anybody can shed anymore info or possibly the title of the movie, it would be so appreciated.

thank you all for you time ^^

Sounds like Little Nemo: Adventures in Slumberland (1989), except the mouse part.

thank you quin

ill have to wait to show the trailer to that movie to my girlfriend and see if it's that

if not, ill be back here again ^^