Spirula is the only genus of squid with an internal shell, a relic of their ammonoid ancestors. When Spirula die their fragile shells float to the surface and are collected on the beaches as "rams horn shells" - this one is encrusted with barnacles.
The colorful mantis shrimp puts on a fearsome show to scare off an invader in California waters, as seen in the IMAX 3D film “Deep Sea 3D,” distributed by Warner Bros. Pictures. - Photo by Michele Hall
Swimming in a glowing, underwater sea of jellyfish would be a really beautiful experience. But, with limited access to the deep sea, this interactive installation by artist Takahiro Matsuo could be considered a backup to that kind of actual encounter.