Season 1, Episode 4. This episode deals with political correctness, offensiveness, and how to deal with offense. The episode introduces the character of Cassius, a vulgar and rude caricature of a middle-eastern man (purposely made to both look and act offensive) who lives behind a fence.
The zone known as limbo is surrounded by a fence of impenetrable repulsion erected long ago by the Spirits in order to prevent the souls of limbo from recognizing, differentiating, or celebrating any diversity between one another.
The souls in Limbo get incredibly offended when you try to call them names (even simple names like "Mike") and must kill anyone who calls names until they stop calling names. They resent the notion that their entire physical and conceptual existence can be reduced down to a fluttering squeeze of ones larynx. Alpha dies many times this episode in an attempt to give his friends a verbal identity. Alpha was angry at Cassius for introducing him to the concept of names resulting in his multiple deaths and wanted to fight Cassius because of it, but he was unable to until he could get past a fence that blocked him. Eventually he learns that the way to deal with a fence is to just get over it.