You could own a laptop for years and never open it up to look inside, but if you do you might find something unexpected.
Apple customers across the world have reported incidents of finding coins inside their MacBooks, and nobody is sure exactly why this is happening.
Some have suggested the money has fallen inside the laptops while others have blamed an Apple conspiracy or, an even more extreme theory, witchcraft, Daily Mail reports.
Last week an Imgur user posted photographs revealing a quarter inside the plastic coating of his MacBook's SuperDrive.
The user said they could not work out how the coin got there.
But this is not the first time - the incidents of finding coins, reports Gizmodo, date back as far as 2010.
In a 40 second video posted on YouTube, another customer called Greg Kilpatrick showed a quarter he found in his computer.
"Same thing happened here, and I can't find anyone who knows why it is there. I have a 1970 quarter," one commenter said on the video.
The most common explanation offered by people discussing it online is the coins have fallen in or been pushed in, for some reason.
"We'd find stuff like this all the time," said one commenter on the Gizmodo article, who used to work for Apple's Genius Bar tech support.
"Ninety per cent of the time, it was the result of kids shoving things in the Optical Drive.
"We'd find coins, paperclips, SD cards, you name it. If it was slim enough to fit in the slot, we'd find it in there."
Another user said strange objects falling inside laptops is common.
"Can't count the number of interesting things I've pulled out of macbook super drives," Reddit user eljefe87 said.
"Clothes tags, hairpins, money, toothpicks, playing cards, etc. Sometimes there's even a DVD!"
Later in 2010 another photo surfaced on Experts Exchange depicting a penny similarly caught beneath the plastic shielding.
In 2013, a photo of a Canadian quarter trapped inside a SuperDrive was posted to Mac Rumors.
Some have said the coins could be offering a kind of support to the laptop, for example fixing a defect in the drive.
But others disagree. "Why would it be a coin, why would they not make a separate piece to go there... very strange,"' said one commenter.
Other people offered less logical explanations, including one commenter who said "this is a form of witchcraft."