Don't even try to make money of a foreign IP... just as DiegoSLTS said, the Nyan Cat creater has a history of hunting down infringement, but even without that, I would stay away.
Some people get away with releasing free-to-play titles infringing popular IPs (there was a big Naruto web game in Germany some years ago, it was not commercial though)... but even that, depending of whose IP you infringe, is a bad idea and can cost you lot of money.
Just come up with an original idea, and you will be fine.
As to the game idea... cow clicker. So click, much fun. Wow!
But I am pretty sure you will find enough fans of such a "game" ;)
