sinking airship

flying, crew{1}{x}
sinking airship gets +1/+1 for
each creature crewing it.
if {x} is 3+, sinking airship loses flying
and gains reach.
if {x} is 6+ sinking airship loses reach, gains
shadow and, "whenever it deals combat damage
to a player, draw a card and deal 1 damage
to any target for each creature crewing it."