Chalk this one up in the ridiculous category, I guess, but here is a video from July of melodic death metal band ChthoniC playing at a show in Japan and decide to bring out former K-1 fighter and the guy currently slated to work for GLORY's Japanese show as an announcer, Musashi. The fighter last seen being picked apart by Jerome Le Banner in a K-1 ring made his way up on stage and then, well, did his best death metal vocals and let's just say that he should stick to his day job, whatever that is now.
PS: Musashi, the secret to doing vocals like that is to drink warm liquids before to relax your vocal chords, they should be coming from your fake vocal folds (this is a real thing), and not the back of your throat, so you can project better while doing those and to not blow out your vocal chords. Maybe next time. [source]