Mysterious plant in the olive grove - capers!

I really wonder what kind of plant this can be? Anyone who knows? Small green pumpkins cracking after a while, and the red inside becomes the
outside!

Growing close to the ground.

I didn't want to look too close, after my post about squirting cucumber...:)
-You never know!

This one is photographed in the olive groves on Crete.
Well, what do you think?

July, 2013
One day I saw the flowers on the same plant, so I know it's capers now. I thought capers were much smaller, but I guess they're just picked earlier.