Anyone know what movie this is? I remember bits and pieces from childhood.?

It's a cartoon, probably at least 24 years old. The one scene I remember is a british looking guy, maybe with a long black mustache, and his buffoon assistant in a row boat out in the ocean. They have some sort of magical gun that they're shooting up at the stars, detroying constellations that are shaped like elephants. They're evil people, laughing as each elephant dies. Then they point their gun at a giant elephant constellation. It takes them 3 or so shots to finally kill that one. Weird, but it's been stuck in my head since I was like 5, and I'd like to figure this one out before I die one day.