Prison School, Sentou Hakai Gakuen Dangerous Recommendations
Both take extremely crazy settings and make the protagonists act 100% serious through them. SHGD is so serious that the for the first four chapters you believe you're reading a lame battle shounen. If you took Prison School, turned the underground student council into delinquents and gave them horribly stupid shounen superpowers (that rivals One Piece), and they killed each other in gruesome (but funny) ways, you're pretty close SHGD. Oh yeah, both are extremely funny and have a fetish for body fluids.