People can say they have copyrights about their works, creations or even ideas, but before the law you can't rightfully argue and say that such creations are belong to them, not without paying the copyrights, this may be Griffnuff's creations, but he/she can't sell them like propierties since he/she doesn't have any official ownership of any of this, the thing is this thing he/shes doing may be illegal.
Also, those colorful cat things are ugly, but that's just an opinion.