Which iOS spin-off is based on World at War's Nazi Zombies mode?

Which iOS spin-off is based on World at War’s Nazi Zombies mode? World at War – Zombies is the answer.

Call of Duty: World at War – Zombies was an iOS spin-off developed by Ideaworks Game Studio and Treyarch and published by Activision. It adapted the Nazi Zombies survival mode introduced in the console and Windows versions of Call of Duty: World at War.

The game first released for iPhone and iPod touch on November 16, 2009, followed by an iPad version on April 1, 2010. Players defend barricaded positions against increasingly difficult waves, earning points to buy weapons, perks and access to new areas. Cooperative play was available through local wireless connections and the internet.

Its maps included Nacht der Untoten, Verrückt, Shi No Numa and Der Riese, connecting the mobile game to the broader Zombies mythology. Black Ops – Zombies was a later iOS sequel, which is why it can be confused with this title. Heroes and Strike Team were separate Call of Duty mobile spin-offs, not adaptations of World at War’s Zombies mode.