Star Wars. The Star Wars universe is very expansive, full of life, and the lore goes really deep. Halo is nothing compared to Star Wars. Throughout the movies, the Jedi easily take down countless numbers of genetically engineered soldiers. In halo there is a very small amount of Spartans(which are basically the same thing as Storm Troopers). The UNSC would be an easy target for Star Wars. Also, the covenant should be no problem. If one Spartan can blow up 3 Halos and slay the covenant, Star Wars should be able to handle it. Same with the flood. The force can overcome anything that the Halo universe throws at it. While Halo would lose very badly, it will still be a cool fight. I would love to see an ATAT fight a Scarab.