"Cats Don't Dance", AKA one of the most underrated animated movies ever.

The 2 whole reasons for it's underrated-ness:

1: Hercules (1997 animated Disney film)
2: Warner Bros did not wan't to spend a lot on advertising.
In fact the Director was furious at WB for making that decision.

Also: This movie won best animated picture at the 1997 Annie awards.