There's a piranha in the classroom.
He's big and green, and he doesn't seem to mind that he's out of water. Just as long as no-one ever tries to feed him a banana.
But he will only be a piranha for one day.
The rest of the week, he's Oscar Kinder, a six-year-old student from Ashmont Public School.
"[For book week] I'm a piranha from [Aaron Blabey's] Piranha's Don't Like Bananas," the student explained.
"Because I like piranhas and I don't like bananas."
The costume looked more than cumbersome, but the young piranha assured it wasn't so.
"I don't need to take it off, but I can if I need to," Oscar said.
While Oscar chose to become his favourite work of fiction, some of his peers chose to pay homage to their cultures.
Yiramir Sharndil, 6, came as a kangaroo and Sonny Malcolm, 5, was the Aboriginal man "who likes to shake his legs".
"He loves shaking his legs too," Yiramir explained of the choice.
"My book is about the kangaroo that hops around to get its tail."
One of the more colourful contributions to the day was Talara May, 7, who came as "the bird that got its colours" from the Aboriginal Dreaming Time tale.
"My mum and dad made [the costume] with me, it took us nearly the whole day," Talara said.
"I'm losing feathers everywhere. [It looks like] I'm dying and I probably won't have any by the end of the day."