I guess you haven't seen Petarded (Family Guy Episode 6 Season 4, http://en.wikipedia.org/wiki/Petarded) in which Peter is all of the sudden diagnosed with Mental Retardation.Originally Posted by Comby
And make fun of that for half a show, examples of this:
Putting a "Caution Special Dad" sign post near his house
Him having to use "Water wings" and a helmet while eating soup
Someone forgiving Peter for running over Tom Tucker (the news reporter) just because he is Peter, the retarded fellow.