They do Glacks evil biddings and they have been known to lure young adults to kill them.
The Radioactive Uber Clan has been trying to break Glacks brainwashing. So far only two children were broken from the brainwashing and are now with the RUC since Glack killed their parents.
It has been known that Glack turns more children into Corn Children. The difference between the Corn Children he brainwashed in front of Mr. Rogers and the children he is recently brainwashing is that their mindwaves are weaker, making them easier to snap back to normal.
If one were to come across a brainwashed Corn Child, toss holy water in their face. That'll temporarily stop the brainwashing.