Necron Monolith

Flying, indestructible
Whenever Necron Monolith attacks, mill
three cards. For each creature card milled
this way, create a 2/2 black Necron Warrior
artifact creature token.
Crew 4 (Tap any number of untapped
creatures you control with total power 4 or more:
This Vehicle becomes an artifact creature until
end of turn.)