When you shoot a spectral arrow at an enderman, it will affect him, he will get the white border around him like every other mob that gets hit by the spectral arrow, while enderman are supposed to not get hit by arrows.

How to recreate? = simply shoot a spectral Arrow at an enderman and voilla! The enderman wil have a white outline! (minecraft 15w31b)

NOTE : I did some testing and it seems that the spectral Arrow is the only Arrow that affects the enderman.