... known by locals as 'Los Monstruos' which means 'The Monsters'.
Mexican police have displayed steel behemoths that could have rolled off the set of a post-apocalyptic action movie that were seized in a raid on an workshops suspected of modifying vehicles for a drug cartel in Tamaulipas, a coastal state not far from Texas.
They have now captured 20 of the converted vehicles that are used to carry drugs, arms and gang members through Mexico and engage rival gangs in violent confrontations.
Some of the vehicles are based on large pick-up trucks such as the Ford F-Series, but the big Monsters are built on heavy duty three axle trucks. Custom bodies are covered with one-inch thick steel panels to repel not only bullets but hand-grenades.
In fact, a military spokesman says: "To destroy this type of vehicle you would need anti-tank weapons."
The most advanced of the vehicles features small openings for snipers and special swivelling turrets, while there is room for up to 20 gang members inside. The steel walls appear to be lined with a plastic coating perhaps for dust sealing and sound deadening. There are also airconditioning ducts, bars for occupants to hold onto and benches.
Some models feature sturdy steel battering ram nose cones similar to vehicles pushing their way through snow or ice, but these are apparently designed to plough through barricades or other vehicles.
Exposed tyres appear to be a weakness and authorities have disabled at least one of the 'tanks' by firing at the rubber. Many military vehicles feature special run-flat tyres with solid rubber inner sections that allow for operation after direct bullet hits, but it is unclear whether any of the Monsters are fitted with these.
One of the workshops discovered by Mexican authorities had used a tipper truck for a base, while three prime movers with large sleeper cabs appeared to be next in line for conversions.
Experts suggest the development of the vehicles indicates drug gangs might by preparing to launch counter attacks on the military that has stepped up action against the gangs violently fighting for control of the lucrative drug supply lines to the US.