He is first seen on a wanted poster (suggesting that he had committed enough poaching crimes for him to be on the run from the law). His first on-screen appearance is him approaching one of the traps he has set, only to be surprised by having caught Cody. At first, he tries to persuade him that he's not a poacher, and seems prepared to let him go, but when he realizes he knows the location of the great Golden Eagle Marahute, he admits that he is a poacher, and has already caught the father. He tosses his backpack to the crocodiles to trick the authorities into thinking Cody was eaten and kidnaps him.
At first he tries to persuade Cody to reveal the location, offering him a 50/50 deal on the sale. Although it's unknown whether he would have kept the deal, he does seem genuine. However, Cody continues to refuse his deals, and he contemplates torture, but when Joanna steals his chicken eggs, he is inspired to tell Cody that Marahute is dead, and that there's no point to keeping him, then mentions casually that her eggs will go cold without her.
At the film's end, as he tries to kill Cody to keep him from tattling on him about his capture of Marahute by feeding him to the crocodiles of Croc Falls, he's knocked into the river by Joanna, who was chasing Bernard. There the crocodiles then turn their attention from Cody to him, and attack him and Joanna. But at first, he seems manages to fight them off, saying "You'll think twice before messin' with Percival McLeach!". However, as it turns out, the large reptiles were trying to escape a huge waterfall, and even Joanna, who has swam to shore, has informed him of it by waving goodbye. He then discovers his fate, and tries to escape, but he is eventually swept over the falls and possibly dies from either drowning или the impact of the fall, ending his malice for good.