While he is the secondary antagonist of the film, he is responsible for the piranhas entering the water park, making him the cause of many deaths.
He is a rude, cruel, greedy, selfish, pompous, arrogant, obnoxious, disrespectful, manipulative, iniquitous, truculent, sadistic, cunning, serious, desperate, opprobrious, argumentative, unmerciful, and impatient businessman who focuses only on the water ride park he has built and the tons of money he will make off of it.
He is also the stepfather of Maddy, one of the girls in the film and the co-owner of the park, and is very perverted. He aims the park for women and plans on seducing them into giving him money.
As the film moves on, Chet is shown to be pumping water into the park from an underground lake which means he is doing illegal activities to boost the park. Maddy is threatened into keeping quiet about it.
During the opening of the park, Chet watches in dismay as piranhas begin to burst out of the pipes and eat people. He cowardly refuses to help any dying survivors and runs. Fearing for his money and business, he runs out the park into the pool allotments. He meets a young girl whose mother has been killed by piranhas. When she looks at him in accusation, Chet arrogantly says "It's not my fault" (when it obviously is) and gives the girl some money, callously spraying it on her mother's corpse. Then Chet gets in his truck and drives off. But he reverses over the girl and kills her. In his panic to get out, he drives into a wire and decapitates himself (most likely accidentally). His head lands in a woman's hands and then, gets thrown to the pool where the piranhas eat his head.
- Chet is very similar to John Hammond's portrayal in the novel, as both characters are greedy and rich businessmen who created an entertainment theme park to give fun for people for their greedy desires without even helping them when danger comes but ended up in dismay after their theme parks ended up being bloody nightmares and even tried to escape it only to get killed with their park as well.
- Although the piranhas are the titular antagonists in the franchise, the true villain in 3DD is Chet, since he is indirectly (and inadvertently) responsible for the piranhas invading the park, and because he had bigger plans than anyone else.