hhahahaa, i would do anything to see a modern day war elephant xD
it'll bugger up your car too though...which makes them a great thing to have in a car chase, speeding along, throw handfuls of caltrops out the window, burst the pursuers tyres and cause them to crash ^^
also depending on how good the rigidity of the caltrop, it may puncture shoes too and would make a great thing to step on foot pursuers
basically a really good easy portable booby trap, not the most advanced though, after all its just something spikey xD (you can also make them buy welding 4 nails together, just cut off the tops of the nails, and weld them together like a pyramid where the tip of each nail is where the corner of a triangle based pyramid
simples