Susanne Eliasson, 55, had just walked into the bathroom of her apartment in Sweden when she heard a loud splashing sound coming from inside her toilet.
She lifted up the lid and was shocked to discover a live rat.
Ms Eliasson frantically tried to flush the rodent down the toilet, but the creature refused to swim back the way it had come in.
Today, Ms Eliasson described the moment she heard the rodent splashing around in her toilet in the southern city of Gothenburg at around midnight.
He said she quickly realised the noise must be coming from ‘something alive’, but had to go through the nerve-wracking task of lifting up the lid to see what it was.
“I guessed it must be a snake or a rat, and when I spotted it I knew I had to take a picture, otherwise no one would have believed me,” she said.
“I was a bit freaked out about the fact it was trying desperately to scramble into my bathroom.”
According to local apartment manager Henrik Mortensen, rats in Gothenburg have recently become a big problem.
“It’s not unusual for them to get into the pipes, but it’s really unusual for them to come up through the toilet,” Mr Mortensen said.
He added that the recent cold spell has driven the rodents underground into sewers.
Rats can swim for three days and are able to hold their breath underwater for up to three minutes.
Their ability to squeeze into the smallest of spaces means crawling through manhole covers and grates poses no problems.
Their sharp claws, meanwhile, allow them to scale almost any vertical surface, making going up the internal pipe system relatively straightforward.
Sewer systems can be food-heaven for the rodents because a large amount of food, including the odd pet goldfish, is flushed down the toilet.
If they get desperate, human faeces can contain undigested food that the rats can feast on in a process known as coprophagy.
And if someone flushes, the creatures can easily swim back out into the drainage system – unless, as in Ms Eliasson’s case, the rat deliberately resists doing so.