Artifact Truck

Reach, Vigilance
If Artifact Truck attacks and is not blocked
sacrifice it and destroy up to 4 target Buildings
and up to 4 target Worker creatures defending
player controls.
When Artifact Truck blocks or is blocked, it may
tap. If it does, tap target creature blocking or
blocked by Artifact Truck. That creature remains
tapped until Artifact Truck untaps.
You may choose not to untap Artifact Truck
during your upkeep step.