Bill Bluff is the main antagonist of the film, where he pollutes Lucky Duck Lake and tries to destroy the monster who resides there. When Doug and Skeeter find out about his plan, by noticing that his agents have been stalking them, they kidnap the monster and the boys try to get the cops to stop him, but since they get bribed by him, they spare him and don't believe the boys.
Later, at the dance were he and his agents plan to get rid of the monster, Doug, Skeeter, and the Sleech twins save Herman the monster and return him to his new home in Crystal Lake and defeat Bluff. Bluff confronts Doug and Skeeter and threatens to make their days a living nightmare but then Beebe appears and defends her friends and tells her father to discuss whatever he wants to tell the boys with her and then Mayor Tippy Dink appears and asks Bluff to discuss his pollution problems which her to which he does and is escorted out by Beebe and the Mayor. In the end Doug explains that Bluff volunteered to clean up Lucky Duck Lake, which he polluted to try to find Herman to which he cleans up the lake.
- Bluff has also done many illegal things such as rig a contest, get government agents to go inside a house without a search warrant and bribe authorities.
- It is revealed in Doug's Secret of Success, that he wears dentures because he thinks brushing his teeth is a waste of time.
- A running gag throughout the series is that he gets Doug's name wrong.