I remember seeing this as a child and for some reason it stuck with me because it was frightening. I think what was frightening about it was that the man got the egg but the monster caught up with him, which is really unusual for a cartoon.
So what I remember is a clip of a guy who enters a cave, and you see the side view of the cave. The man has to swing on some vines for whatever reason, and his target is apparently an egg that he actually is able to grab. However, there was some sort of humanoid monster in the cave with him and it caught up with him and pulled him down. I think the clip ended after that. Not sure what this was from but would be cool thing to find out because I've always wondered if there was more to the story!