Christopher Orlando Torres creator of Nyan Cat and Charles Schmidt Keyboard Cat's owner have filed a copyright complaint and trademark infringement lawsuit against Warner Bro. as well as 5th Cell of their creations appearances in the Scibblenauts series.
It was filed on April 22nd, and 5th Cell did not ask for permission to include these characers in their published products or for the promotional materials.
Warner Bros and 5th Cell's trademark infringement was said to be intentional. Keyboard Cat has appeared in all of the previous games but Nyan Cat has only appeared in Scibblenauts Unlimited.