Ok, cats = fabulous. So you got me on the heart factor. Plus them cuddling, adds cute factor. Plus killer processing and the whole yin/yang, hugging thing. BUT, technically not really underexposed. On the contrary, this is a bit overexposed. Love it anyway.
Hell of a shot in so many ways, but it's not speaking to the challenge topic for me. The defining characteristic of this image is more OVERexposure than UNDERexposure, it's a pretty much high-key shot. I like it very much, however.
I've been fairly flexible on peoples judgment of what is an underexposed photo, but this is clearly OVERexposure, I'm afraid. Plus a bit of camera shake.