Vampire squid a human's inner ear) and ammonium-rich gelatinous tissues closely matching the density of the surrounding seawater. Like many deep-sea cephalopods, the vampire squid lacks ink sacs. If disturbed, it will curl its arms up outwards and wrap them around its body, turning itself inside-out in a way, exposing spiny projections. If highly agitated, it may eject a sticky cloud of bioluminescent mucus containing innumerable orbs of blue light from the arm tips. This luminous barrage, which may last nearly 10 minutes, would presumably serve to daze would-be predators and allow the vampire squid to disappear into the blackness without the
Whip-lash squid and "Idioteuthis" are known to have expanded tentacular clubs as paralarvae (for both species) or adults ("Idioteuthis"). Members of this family have scarcely been observed in life, but at least two species ("Mastigopsis hjorti" and "Magnoteuthis magna") are known to hover above the ocean bottom in a vertical orientation, the head pointing downward. The squid use their large fins to maintain this orientation and use both their extended tentacles like fly paper, held rigidly at a constant distance apart: this has been termed the "tuning fork" position. Prey items apparently consist primarily of benthic crustaceans. Although mastigoteuthids possess ink sacs