User blog comment:Itsleo20/PvZ Youtube Series/@comment-25091708-20140821012320

Actually first Wall-nut and Potato Mine will be stuck in an abyss, but Potato Mine finds a void portal that sends him to the Endless Skies. So Wall-nut is in the Abyss, and Potato Mine is in the Endless Skies. But both of them there will work too.

Concept art made in paint: It's an example of the endless skies, it's a rough sketch.