We had one under the fridge once. It had been a warm humid night (unusual here in Hobart) around Christmas time and i groggily walked to the kitchen after getting up, saw a head poking out from under the fridge and thought...gee, that's a rather large lizard. Then I realised it didn't have any feet. We boxed in the base of the fridge and called Reptile Rescue. It turned out to be a tiger snake - one of the most venomous - but thankfully not very large, about 18 inches. The lovely Rescue man said it had "chew marks" on its neck - so must have been brought in by one of our cats. We'd previously built a cat proof fence around our back yard to keep the cats in and an afterthought was that it would keep snakes out. However I discovered a few places where it may have got through and blocked all those.
Our Rescue man took a while to arrive as he was diverted to another suburb for another snake on his way to us and he'd previously been called out at 3 am that day to a snake under someone's stove at Seven Mile Beach, 25 km away. Fortunately snakes disappear during the colder months in Tasmania so they are not a problem year round.