I was thinking about Type: Null today and wondering what Pokémon he is made up of, me and my friend talk frequently about theories etc before a new Gen and he postulated that it is probably a combo of the Starters in some way, this is mainly backed up by the fact that it has a big cat head.

Now I don't recall where but I remember one of the leaks a while back talking about a new "Cat" Pokémon that can inherit a secondary typing from one of it's parents and it will change the way it looks slightly?

Well what if that "Cat" IS Type: Null? Type: Null is probably an experiment to make a Pokémon that is all types at once, well if this Cat Pokémon exists then surely it is all types? Not at once granted, but just like Eevee has the potential for all it's evolutions in it's DNA then this cat must have "Multitype" DNA in it somewhere. Is Type: Null a group of poor tortured/genetically manipulated Cat Pokémon?