"What the blazes?"
Liam's hatred of platypus started at a young age. In Australia, his mother was distracted by a platypus, leaving Liam and his stroller to roll away. Ever since then, Liam made a living by hunting down platypuses. He also carries a collection of boomerangs (even giving them lady names to suit his purposes), which he uses as weapons, even one can be able to cut down a large tree.
Upon learning of Liam's occupation from an evil consultant website, Heinz Doofenshmirtz decides to hire him into capturing his nemesis, O.W.C.A. Agent Perry the Platypus. To do so, Doofenshmirtz lays out smoke signals to lure Perry to the Danville Botanical Gardens, where Liam traps Perry. After Liam explains his backstory to the two, Liam start to introduce his boomerange collection, which starts to disturb Perry, even Doofenshmirtz finds it to be creepy.
At that point, things get out of hand when Liam announces that he's planning to kill Perry and make a trophy out of him. This doesn't look good for Doofenshmirtz, who objects to this, saying that this wasn't part of the deal. However, Liam betrays Doofenshmirtz by trapping him and handcuffing him to Perry, threatening to make a trophy out of him too. Liam then gives the two foes a 60-sec headstart so that he can hunt them down, forcing the two to run.
Having no choice, both Doofenshmirtz and Perry are forced to work together to defeat Liam in his game. To do so, they create a series of traps using the garden's habitats. Despite their efforts, Liam proves to be stand ground before engaging into a boomerang fight with Perry. Just as soon Liam finally manages to pin Perry down and prepare to kill him, he is stopped by Doofenshmirtz, who have called in the garden's groundkeepers to the scene, explaining that Liam has damaged much of the garden's habitants with his boomerangs while chasing Perry. Realizing that Doofenshmirtz is right, the groundskeepers force Liam to spare Perry and escort him out from the gardens. It is later revealed that Liam isn't of Australian descent, as the groundkeepers revealed that his files says that he came from Pittsburgh, so his Australian accent was fake. He is last seen being rolled down on a wheelchair screaming as the groundkeepers are distracted by Perry's appearance.
Liam can be described as a heavy-built man with a thick brown mustache, black sleeveless shirt, and fingerless gloves. He also wears boots aided with spikes at the sides (referenced from the poisonous spurs that male platypuses have on their hind feet which are used for defense).
- When he is first introduced, he is called "Liam O'Cracken". He is even referred to as such in the Disney Channel promo for the episode.