When a pair of almost footprint-shaped marks suddenly appear on your ceiling, there's two things you need to consider.
The first being, is it mould?
And the second simply requires you to rule out whether Lionel Richie's been round to yours recently and started throwing shapes on the ceiling. You know what he's like for chasing that feeling.
But if you're still stumped after following this process of elimination, like this woman was, you might want to check you haven't got any unwanted guests in your home.
Advert
Otherwise, you're going to be left with quite the gruesome mess on your hands.
An anonymous female renting an apartment explained that the ceiling in her home had been plagued by strange spots that don't 'feel soft or wet' which kept showing up continuously.
So, as anyone would, she took her dilemma to Reddit in the hopes of a social media user offering up an explanation and a solution.
The tenant said that she had checked with the person living above her that they weren't experiencing a leak, their floor wasn't wet and that no water was turning up in their pad unexpectedly.
She had flagged the issue with her landlord too, although she claims that maintenance crews sent in to remedy the issue would just 'spray ceiling paint over them [the spots] each time'.
"The spots originally were more in the corner but have moved," she wrote. "Always two spots, about the same size. I am a renter, so I cant tear out the ceiling or anything.
"I want my apartment complex to actually find and fix the issue not just keep 'fixing' the spots with paint! Help!"
The woman also shared an image of the dark coloured marks that were smudged across her white ceiling, proving it was an eyesore as well as an enigma.
She explained she initially believed the marks were caused by mould, but the real reason behind the brownish patches was arguably even worse.
Her post attracted hundreds of comments as Redditors rushed to give their advice.
One wrote: "I had these before. Thought it was reappearing stains. Found out it was mice p***ing in my attic."
Another added: "That's a lot of mouse p**s."
A third wrote: "It's rat pee soaking through!"
And a fourth added: "Brown stains that appear in different places is rodent pee."
The woman then told social media users that her son had 'smelled' the area and 'confirmed' that it was the work of some rodents with full bladders, as it smelled a lot like his hamster's cage.
Well, where did you think the term 'to smell a rat' come from?!
How to prevent rodents invading your home
To avoid a gang of rodents ruining the state of your ceiling, there are a few precautions you can take.
The British Pest Control Association (BPCA) suggests you should protect your property by sealing any possible entry points where mice, rats, or anything in between could sneak inside.
You can secure areas such as gaps, vents, pipes and windows with wire wool embedded in quick-setting cement.
As well as this, the BPCA reckons that you can deter rodents by removing potential nesting sites and keeping your garden tidy, preventing access to household waste, storying food correctly and keeping up good hygiene practices.
They might be furry little creatures, but these lot can cause 'serious' harm by spreading diseases such as Salmonella and Listeria with their urine and droppings.
How to get rid of rodents in your home
Rodents are plucky little things which are 'hard-wired to survive', according to the BCPA, so it's not exactly easy to evict them from your home.
The pest control experts suggest that Brits should contact professionals to deal with an infestation in most cases, as they have a 'range of professional use rodenticides which are not available to the public'.
"Amateur-use products are restricted and it is likely that you won't be able to purchase the necessary poison," it adds.
But if for some reason you fancy having a crack at getting rid of the rodents in your pad, the BCPA recommends picking up some amateur-use rat poisons (rodenticides) and traps from a hardware store or garden centre.
Although success might be slow, it's certainly a lot cheaper than roping in the big guns.
If, like the Redditor, you are living in rented accommodation and run into a vermin problem, the good news is - it's probably your landlord's job to deal with it.
Olivia Burke