Piglet Squid, Helicocranchia pfefferi
"This funny looking squid is about the size of a small avocado and can be found most commonly in the deepwater (greater than 100 m or 320 ft) of virtually all oceans. Its habit of filling up with water and the funny location of its siphone with a wild-looking 'tuft' of eight arms and two tentacles had prompted scientists to name it the piglet squid."– Zooillogix
Voilà, a strange little find from the deep seas! Not too much info about these guys online... but for some reason, they really seem to swim like this (upside down?).