A mysterious, many-armed sea creature — initially described as a large "red glob" — lying on a rocky shore in Washington has drawn in cephalopod experts across the country, each wondering what this gelatinous animal is. The 3.5-foot-long (1 meter) beast's identity was at first elusive; was it the shallow-water East Pacific red octopus (Octopus rubescens)? Or perhaps it was a very lost deep-sea vampire squid (Vampyroteuthis infernalis) or a deep-sea dumbo octopus (Grimpoteuthis)? The likely answers (no, no and no) led scientists to yet another species: the seven-armed octopus (Haliphron atlanticus), a deep-water creature that is rarely seen as...