Jeff Rotman / Giant Pacific octopus squirting ink at diver, British Columbia Canada

Fred Bavendam / Pacific Giant Octopus (Enteroctopus dofleini) squirting ink in defense as it jets away, Quadra Island, British Columbia, Canada

Jeff Rotman / Giant Pacific Octopus (Enteroctopus dofleini) swimming, squirting ink at a diver, British Columbia, Canada, Pacific Ocean. Model released.

Francis Abbott / Common octopus (Octopus vulgaris) releasing clouds of ink when feeling threatened by a diver, Mediterranean

David Shale / Deep sea Glass squid {Cranchia sp} from Mid-Atlantic Ridge, squirting ink

David Shale / Deepsea Glass squid {Cranchia sp.} squirting ink, Atlantic

Norbert Wu / Octopus (Octopus sp) mother brooding eggs in an empty beer bottle, spraying cloud of ink as defense, Sulawesi, Indonesia

Norbert Wu / California Sea Hare (Aplysia californica) ejects purple ink when disturbed, California

Norbert Wu / California Sea Hare (Aplysia californica) ejects purple ink when disturbed, Monterey, California