This is true.
I was staying at my uncle and step-aunts house to babysit my 6 year old twin cousins. The house was right beside a swamp in Canberra. I was about 14 – 15 years old at the time. I had just put my cousins to sleep when I heard a squelching noise in the swamp. I assumed it was a wild animal, a cow or sheep that had got lost.
I ignored it and the squelching continued for about 20 minutes before slowly stopping. After maybe, half an hour, a low, distant croaking started. Assuming it was swamp toads, I wasn’t scared, but for fear of my cousins waking up, I shone a light out there. To my horror, there were no toads.