Katsuhiro Otomo’s Watermelon Messiah. There is a high-res copy of the truncated version of this story that appeared in ‘KABA’ and a very low-res copy of the full version which you can’t get anymore. Anyway, I stitched the two together.
UPDATE: I found pictures of how this comic originally appeared in a special edition of Young Magazine (September 14, 1981), so I added ‘em to the bottom. It appeared in this foldout 655 x 250 dimension format. The story was introduced with the text:
"In the distant future, the starving and thirsty people of a devastated civilisation witness a messiah from a distant planet."