In the scene where Charles and his father are sitting at the kitchen table, John Ferguson was forced to drink coffee creamer since there was no milk available on set.
Scott Ferguson (Pop) is the actual father of John Ferguson (Charles).
The character of Stephen didn't exist in the first draft of Worm. The role was created specifically for Josh Matthews after he auditioned for the role of Walt.
There was no script written for Worm. The actors improvised their lines from a detailed outline of scenes.