There are two clearly defined spikes in the water reaching up toward the pyramid. It was most evident on these two cubes, although the others in the tray did show smaller versions of the same thing. The spike on the left almost looks like a single terminated quartz crystal.
Unfortunately the spike on the left broke off at some point during the freezing, but the one on the right remained strong:
edit: just tried the same experiment with freezing orange juice and milk, but no spectacular results to share from that, just some frozen OJ and milk