Dead Island creator Techland has trademarked "Dead Stop", a zombie game for mobile devices.
The trademark was filed in the United States by the developer. Dead Stop will be a title for "entertainment services and providing an online game via an application for mobile phones and other electronic apparatus".
Dead Island's trademark doesn't make mention of the aforementioned features, so it's a distinct possibility that this is indeed a mobile game.
Techland's currently working on sequel Dead Island: Riptide. More details will be released later in the summer, with a launch due in 2013. It'll release with a reduced price of $50.