BUILDERS made a large discovery while working on a construction site at Mount Cotton State School.
Tradesmen uncovered a giant moth at the building site on the edge of a block of remnant rainforest.
Work has been ongoing for the past 18 months and the sighting was made when school was closed.
Speaking on ABC Radio, principal Meagan Steward said it was an amazing find.
"Staff and students weren't surprised by the find as we have a range of animals on our grounds... but this moth was not something we had seen before," she said.
She said it was probably as large as two fist sizes, grey in colour and had its wings flapped down.
Ms Steward said one of the classes used the moth as a stimulus for a creative piece of writing with some interesting stories emerging, including a giant moth invasion and their teacher being eaten by the insect.
The builders released the moth into the rainforest after taking a few photographs of the rare find.
Queensland Museum's head of entomology Dr Christine Lambkin identified the insect as a giant wood moth.
Wood moths are the heaviest moth in the world, with some females weighing up to 30 grams with a wingspan of about 25 cm.
Males are only half the size of females.
They are not common, but they are not unusual and are found in Queensland and New South Wales.
Apart from giant moths, crocodiles and deadly snakes like taipans, Queensland also just happens to have the heaviest and one of the largest cockroaches in the world.
The Queensland Museum describes the appropriately named Macropanesthia rhinoceros as a slow-moving, subterranean beast from north Queensland.
The giant burrowing cockroach is about 8cm long, weigh 30g and digs 1 metre deep burrows where the female has live young.
Some Queenslanders even like to keep them as pets.