Probably not. At least, not in "real-time". It makes for good horror and sci-fi, but in reality the energy costs of constantly reforming yourself like that woul

Probably not. At least, not in "real-time". It makes for good horror and sci-fi, but in reality the energy costs of constantly reforming yourself like that would be, shall we say, prohibitive. (Incidentally, at the risk of slight spoilers, this is an issue that is addressed, if slightly obliquely, in Michaelbrent Colling's horror novel _The Loon_.) There are plenty of organisms that have extremely free body plans that can be altered as they grow, however (notably, most plants and fungi), so it's less of a stretch to imagine a creature that could consciously direct changes in its own morphology over long periods of time- equivalent to how long it would take the new structures to grow anyway, if they were a set part of a normal animal's morphology.