 Meanwhile , Homer adopts a pig from Krusty Burger and names it " Spider Pig " ( later " Harry Plopper " , and simply " Plopper " ) , and stores the pig 's feces ( and some of his own ) in a silo , until Marge tells him to safely dispose of the waste . Homer intends to take his silo to the waste management plant , but after Lenny ( Shearer ) calls to tell him that Lard Lad Donuts has been shut down and is giving away free donuts , Homer impatiently dumps the silo straight into the lake , polluting it again . Moments later , a squirrel jumps into the lake and becomes severely mutated ; Flanders and Bart ( who bond after Homer humiliates Bart ) discover the creature before the EPA captures it . Russ Cargill ( Albert Brooks ) , head of the EPA , presents five " unthinkable " options to U.S. President Arnold Schwarzenegger ( Harry Shearer ) to keep the town 's pollution contained ; he steers the slow @-@ witted president into enclosing Springfield in a large glass dome . When the police discover Homer 's silo in the lake , and his responsibility for sealing Springfield in the dome , an angry mob advances on the Simpsons ' home to kill Homer , but the family escapes the town through a sinkhole , which then destroys their house . With the EPA on their trail , the Simpsons flee to Alaska . On the way , Homer tries to make some money at a carnival by riding a motorcycle around the inside of a metal cage . 
