No one knows what evil intelligences possessed these seemingly normal Ancient vehicles, but everyone on the roads of Gamma Terra fears the deadly hum of their malevolent engines. Stats for three killer cars here: compact cars (level 4 skirmishers), SUVs (level 5 soldiers), and Fire-Belching, Car-Devouring Monster Truck!!!s (level 6 brutes).
Inspired by a twitter discussion with @battlejack.
Update: Here's a bonus monster, an elite killer car: