The WWE is obviously trying to get their ratings up any way they can, and decided that since everyone loves cats, it was time to get the most well-known cat of all involved.
That's not the only reason that the now famous internet feline was on the show though, as she has her own movie coming out, so it was beneficial to everyone...sort of. Well, as beneficial as having a cat that can't talk host a TV show could really be to anyone.
Either way, she didn't look pleased to be there (no surprise) and was involved in a couple of segments including this one with The Miz, who claimed to be a pretty big fan of her, despite not liking her "smug look".
Not impressed with her stunt double, apparently.
Via Buzzfeed. Main pic via Grumpy Cat/Twitter