I think this is going to be one of the more talked about episodes. In addition to finding out about Eyepatch, we learn more about the monster, and they do more with it. We know it's not a dinosaur of course, and the show's creators have denied it's a nano cloud... My new theory is it's an insect swarm. We know the Hanso Foundation has been experimenting with animal intelligence, so they might have created an intelligent colony. If the insects are telepathic in order to pass information as a whole entity, they could read Echo's and Locke's minds and probably project illusions into them. They might also be psychokinetic in order to do uproot trees and grab people, though the sound accompanying the grabbing and dragging and slamming is that of ratcheting machinery. An alternative would be that the smoke is concealing a machine that may have artificial intelligence and psionics. Hanso probably experimented with machine intelligence as well.