good ideas, and the little bits of pointy metal mentioned are called Caltrops. think sharpened jacks, however you throw thew, they land with a spike pointing up. primitive landmines, basically. they worked on horses, too, but probably not on kran, or maybe only half damage...
Jessyn
BTW, yes, i would like to see caltrops, but they would be VERY hard to implement, unless they only hit hostiles, and had a time limit on the order of 10 minutes...