6/10
OP's suggestion. Get this man some water.
(the part you're looking for is at 4:25)
Rap God was already a pretty solid song, but I live and die for metal in the music world. And doing scream vocals at those speeds is nutty. 9/10 for the song, but 11/10 for the effort put into it. You can just feel it that they went all-in with this cover.