The ability to have no bones.
The user has no bones, often making them highly flexible. Often the user's skeleton is made up of other matter, such as cartilage.
Inklings (Splatoon), like squids, have no bones...
...although they do have teeth.
The Squid Sisters (Splatoon), Callie (left) and Marie (right)
Cap'n Cuttlefish (Splatoon)
DJ Octavio (Splatoon), like all Octarians and octopi, has no bones.
Annie (Splatoon), being a sea anemone, has no bones.
Jelonzo (Splatoon), being a jellyfish, has no bones.
Spyke (Splatoon), being a sea urchin, and Super Sea Snails, like the one sitting next to him, have no bones.
Boneless Chicken (Cow and Chicken)
B.O.B. (Monsters vs. Aliens)