Chromeshell Crab

Morph {4}{u} (You may cast this card face down
as a 2/2 creature for {3}. Turn it face up any time
for its morph cost.)
When Chromeshell Crab is turned face up, you
may exchange control of target creature you
control and target creature an opponent controls.
A deviant form of the Shogun Ceantaur, the
Rustrazor's pincers have metallicized, leading to
stronger strikes