You should watch Dark Star. Jodorowsky was very impressed with it and formed a relationship with the FX designer:
I saw in a modest festival of cinema by science fiction amateurs, a film made without means that I found marvelous: Dark Star. I contacted the boy who had made the special effects: Dan O' Bannon. I was almost with a wolf child. Completely out of conventional reality, O'Bannon was for me a real genius.