After this underwater dog photo, we thought we'd seen all photographer Seth Casteel had to offer of submerged pups. But then we got a gander at more photos from Casteel's underwater dog gallery and knew we were in the midst of a full-blown wet dog phenomenon.

All of the dogs in these photos are simply playing, but most of them -- with the exception of the goofy Labrador Retriever above -- seem to be doing so with rabid ferocity. (There's a lesson here: never get between a dog and his ball.)

According to his website, Casteel is a professional pet photographer who also snaps kitties and takes portraits of owners and their pets. Hmm. Are underwater cats next? Now that's something we'd like to see.