Hi, I'm looking for an 80's (could be late 70's) cartoon movie. All I can remember is a scene where there is a frog king with a very deep voice, who sings a song to the hero's of the film. I can't remember who they are, some small animal I'm sure. I can picture bright, almost psychedelic colors. I have a feeling that the frog king was either evil or crazy. Please help, I've been trying to remember this forever! :(:(:(:(

I can think the scene may have taken place at or near an old water mill.

Is it "The Elm-Chanted Forest"?