first off, Grubflap is not a character I came up with, credit goes to @Nigelninja11, i think. I did however paint it, obviously... After the destroying of Alpha Halo, the Covenant needed a way to counter the spartans that were interfering with the the great journey. The covenant devised a serum that boosted the physical traits of the subject, although it was not quite ready. After the events following Halo 2 the prophet of truth quickly put this into action, out of 200 subjects, only 3 survived, one of them being Grubflap. Due to the serum not being complete, it altered the subjects physical appearance, this gave them a more feral look...
This back story is simply an attempt to remotely like the 343 aliens.
This back story is simply an attempt to remotely like the 343 aliens.