What's Wrong With This Picture?

Sunshiney Yellow Pear Tomatoes--perfect and smooth....

....yucky Hillbilly Tomatoes--they look like someone purposely carved spirals into them.

Did aliens do this to my tomatoes? Some kind of bug, perhaps? There's nothing obviously wrong with the plant. No bugs that I can see. And the Yellow Pear is almost touching the Hillbilly plant (although they are in different pots, and thus different soil) so I would think if it was a bug they would both have it. Any ideas?

(Update: I did some lunch time research and figured out that it's a water problem. Apparently these tomatoes were at a critical stage when I left them to fend for themselves over the Fourth of July. I'm sad to lose a few, but relieved to know that I can easily fix the problem for future tomatoes.)