 While performing on Lake Springfield , rock band Green Day is killed when the lake 's pollution dissolves their barge , following an audience revolt after frontman Billie Joe Armstrong proposes an environmental discussion . At the memorial service , Grampa Simpson ( Castellaneta ) foresees the destruction of the town , but only Marge takes this seriously . Later that day , Homer dares his son Bart to skate naked to the Krusty Burger restaurant and Bart is arrested by Chief Wiggum ( Hank Azaria ) . Bart considers their neighbor Ned Flanders ( Harry Shearer ) a better father figure after Homer refuses to take responsibility for the incident . Lisa and a new Irish friend named Colin ( Tress MacNeille ) convince the town to clean the lake . 
