Legion vs. Phalanx

[Banzai!]

What has always puzzled me is how to actually kill someone with a sarrisa pike? I can't see how you could deliver a thrust with any kind of force behind it. Can a pike even penetrate chainmail?

I always imagined the phalanx just using its depth to walk over an enemy formation, butt-spiking those unfortunates who have been pushed down. I think I know now why Polybius was so surprised after seeing the gladius in action - yes, real weapons do leave cuts.