The Los Angeles Intellectual Property Trademark Attorney Blog reports that Attorneys for Charles Schmidt - creator of Keyboard Cat - and Christopher Orlando Torres - creator of Nyan Cat - have accused Warner Bros and 5th Cell of including the Keyboard Cat and Nyan Cat characters in multiple Scribblenauts titles dating back to 2009 without any licenses or authorizations.
Warner and 5th Cell have also been accused of identifying Nyan Cat and Keyboard Cat by name in the promotion and marketing of the Scribblenauts games.
The IP Blog makes the point that neither plaintiff is entitled to statutory damages or attorney's fees for claims related to the 2009 Scribblenauts title because neither copyright was registered until 2010.
The latest Scribblenauts title, Scribblenauts Unlimited was scheduled for release back in February, but suffered a last minute delay and is yet to be released - although some copies were dispatched by Amazon.co.uk. Given the copyright claims were only made in April, however, it doesn't appear that the game's delay was related to the lawsuit.