Rarely, in cases of parasitic twins, does the subject have control over the vestigial limbs of their sibling. There have been rare cases of control, but when only an extra limb or two are present. Francesco Lentini, for example, exhibited some control over a third leg.

http://www.thehumanmarvels.com/2006/08/francesco-lentini-three-legged- man.html

In this case, however, control is highly unlikely as the twin is nearly complete. A head or brain likely exists somewhere in the torso, thus the limbs are not hardwired to the central nervous system of the subject.

This newest extreme case of parasitic twins, while unusual, is not unheard of. In the 90’s as a man by the name of Rudy Santos was exhibited as ‘Octoman’ in the Philippines.