Does that mean I can't make a game about the Keyboard Nyan Fusion Cat now?
Keyboard Cat creator Charles Schmidt and Nyan Cat creator Christopher Orlando Torres are suing (yes, this is a thing now) Warner Bros. and 5th Cell for their use of both cats in the Scribblenauts franchise. This includes the original Scribblenauts in 2009, Super Scribblenauts in 2010, Scribblenauts Remix in 2011, and Scribblenauts Unlimited in 2012.
They accuse the defendants of "shamelessly using" both Nyan Cat and Keyboard Cat "by name to promote and market their games," and that their "trademark infringement was willful and intentional."
Unfortunately, their argument isn't purr-fectly sound. There's the minor issue that neither copyright was filed until 2010, but the major issue is that Shcmidt and Torres registered their copyright over five years after the videos were published on YouTube, which likely means those copyrights are not legally entitled to a presumption of validity under 17 U.S.C. 410(c).
In other words, hairballs!