Happy Aquarium: Adopt a Lost Baby Axolotl (a.k.a. Wooper Looper)
Lost baby animals in Happy Aquarium is a creature grabbing feature where a pet is only available through the Facebook wall posts of other players. So if you run into one in the game, you can post the prompt to your wall, but someone else will get your critter. Obviously, some cooperation is needed if you want one of your own.
The newest addition to the orphaned critters family is the Axolotl -- a neotonic mole salamander that comes from a lake in Mexico City. "Neotonic" is a fancy adjective telling us that these are salamanders that have failed to grow up into a proper salamander, so they're stuck as infantile gilled lizards. Fortunately for them, this also makes them a very popular pet in America, Britain, and Japan.
So yes, not only is this Axolotl sad because it's been abandoned by his family (according to Happy Aquarium) during a Cinco de Mayo parade, but it'll never know the visible joys of puberty. I think this thing has won the virtual pet sob story of the year, don't you?