You know what's weird about sequels to animated features? There aren't that many of them.

Maybe that's because kids are happy enough to watch "Kung Fu Panda 3" (opening Jan. 29).

And that's not necessarily a bad thing. Some animated sequels have actually been very good, amplifying the original story and finding new depth in the characters, in ways fans might not have imagined. Here are 12 of the best Toons Part II (and beyond).