Of course, it can always only be Aliens. They probably found the surface of the previously existing Earth distasteful and thus decided to get rid of it and put on new floor tiling, before setting up their favorite pets in their new terrarium.
Or they found it to be most delicious, and after consuming all of it, dumped their trash and moved on. The compost left behind then served as a fertile environment for life to explode.
*puts up hands* Now hear me out (Score:4, Funny)
"Aliens"
Re: (Score:4, Funny)
Re: *puts up hands* Now hear me out (Score:4, Funny)