The Saddledome

The Saddledome enters the battlefield tapped.
{t}: Add {b}.
{3}{b}, {t}: Put a shadow counter on target
creature. For as long as that creature has a
shadow counter on it, it's a Wraith in
addition to its other types. (A creature
with shadow can block or be blocked by
only creatures with shadow.)
Minas Morgul, Dark Fortress