 Declan Desmond, played by Eric Idle (qv), asks Homer if he can use  the "condiment pen" on fish and chips, to which Homer replies, "You  can use it to put horseradish on your dead mother for all I care."  This is a reference to a Monty Python sketch, in which Eric Idle  takes his mother to an undertaker who suggests various means of  disposing of the body, finally suggesting cannibalism