Spy, Invisible Killer

This creature enters the battlefield as a copy of
target creature an opponent controls and under
that players control, except it gains "This creature
can't attack or block and it's activated abilities
can't be activated", "{4}{b}{b}, Return this creature
to it's owner's hand: destroy target creature the
controller of this creature controls. Only the
owner may activate this ability" and "{3}: Sacrifice
a creature with the same name as this one at
random."