"Is this what Easter bunny or dog spat out? Yuk," another said.
One user was completely horrified by the eight-legged find, urging Mr Williamson to "burn the house down".
The mysterious spider was eventually identified as an Ordgarius magnificus, more commonly known as the magnificent spider.
These spiders are found on Australia's east coast and, thankfully, pose no threat to humans.
A fully grown female can reach up to 2.5cm, according to the Australian Museum.
Unlike many spiders who build webs, the magnificent spider has a more sophisticated way of catching its prey.
It uses a single line of sticky silk that has a globule attached to one end that mimics the scent of a particular type of female moth.
The smell attracts the male moths and they become trapped in the silk.
These spiders usually hang out in the garden and are great at keeping pests under control.