Urza's Juggernaut

As long as you control three or more Urza's lands, Urza's Juggernaut gets +2/+2 and has trample.
Crew 1 (Tap any number of creatures you control with total power 1 or more: This Vehicle becomes an artifact creature until end of turn.)
Even though Urza built this Juggernaut, the goblins always seem to take it for a joy ride.