Here's an almost-grown up white axolotl (Ambystoma mexicanum) -- a cousin of Punky and his pals, but a salamander who remains aquatic throughout life (instead of undergoing metamorphosis into a land dweller). As a larva, Thumper's dorsal fin served as the host site of another larval axolotl's entire brain, inner ears (with the animal's balance sense organs) and hind leg. The author put a segment of spinal cord in to splice the brain to the leg.
After the transplanted parts took hold, Thumper showed us several interesting things. First of all, if he positioned himself such that the foot of the transplant came in contact with the surface of the dish, the leg would begin walking (showing a plantar reflex) -- independent of what Thumper's own four legs were doing. (The transplanted brain had a mind of its own.) Now if you chased Thumper around the aquarium with a fish net, and he'd swim wildly to escape, the transplanted leg would hammer like a jack rabbit for a while after Thumper would come to rest. (The motion evidently made the transplanted brain sea sick.) Thumper, and the transplanted stuff inside his fin, lived happily in the laboratory for several years.