A human (woman usually) becoming a hollow, inflatable, pneumatic version of her former self. Some kind of a blowup doll. Possibly animate, able to move and speak. Or helpless and indistinguishable from a plastic doll from an adult shop.
Of course, inflation (and deflation) are among options.
Do you find this kink appealing?
I definitely wouldn't mind turning into a inflatable doll, well as long as i could still move, talk and just enjoy life :)