In Piranha 3D he was the deputy of Sheriff Forrester during Spring Break. When Matt´s body was found in the lake, he recommended that the lake should not be quarantined until they would know more about the circumstances surrounding his death through the pathologists. He, like the others, erroneously speculated, that his death was caused by acid.
When it was found out later that it were piranhas who had killed him and that many more were in the lake now, he went with the Sherriff and the other deputies to the lake to warn the tourists, who only got their attention, when he shot his gun several times in the air. It was too late. On the one hand the tourists didn´t want to listen, when he tried to tell them to go away from the lake, on the other hand the piranhas were already nearby. Moments later the piranhas began to attack the tourists for the purpose of eating them. To save as many tourists as possible, Fallon, in a last stand, went into the water with a boat motor. He managed to kill many piranhas and save several tourists, but the piranhas also were eating him.
In Piranha 3DD it was discovered that he survived the day, but that he had also lost his legs because of the piranhas.