"The Mystery of the Severed Feet" might sound like the title of a terrifying Agatha Christie novel, but it's actually a real thing in Canada; at least 15 detached human feet have washed up somewhere in British Columbia over the past two decades.

The ongoing, grisly phenomenon has inspired many questions from Canadians, a segment on David Letterman and even an episode of the hit TV series Bones.

Known to most as the "Salish Sea human foot discoveries," the disturbing occurrences have become so commonplace that they even have a Wikipedia page dedicated to them.

B.C. Coroners Service looking for info in case of foot washed ashore in West Vancouver | CBC News https://t.co/cqy1ct7kbO pic.twitter.com/iAfLvq5Vzq

— Pierre Renaud (@prenaud) February 14, 2019

People around the world continue to be disturbed by the mystery, including many Canadians.

"Not a day goes by that I don’t think about how 14 severed human feet with shoes still on have washed up on the same shore in Canada over the past 10 years," one person wrote.

"What the f*ck is going on with the severed feet in Canada?" another person wrote. "Jesus. That's just wrong."

"I live in the Salish Sea and it's beautiful and I love it but yes it can be creepy as f*ck and I apologize," yet another person said.

seriously canada has a huge problem with severed feet send help

— kels • for funniest account and amy santiago stan (@langindustry) January 19, 2020

For years, the Salish Sea feet phenomenon baffled Canadians, provoking a kind of morbid fascination.

Some people suggested foul play. Others suggested aliens. One person even argued that the severed feet could belong to the missing victims of the Indian Ocean Tsunami in 2004, carried halfway across the world by ocean tides.

But the answer to the mystery is far more sad and straight-forward.

B.C. Coroner Barb McLintock said in 2016 that running shoes act like a flotation device that pull the feet to the surface; the additions of lighter foam and air pockets in recent years increase the likelihood that the feet will wash up on the beach.

"Before, they just stayed down there at the bottom of the ocean," McLintock said.

She also confirmed that coroners had ruled out foul play in all of the cases, meaning that the severed feet came from either suicides or drownings. Ocean patterns then deposit the feet on to B.C. beaches.

B.C. Coroners Service shows the location of where feet were found in British Columbia linked to unidentified human remains as of October 2019

Although Canadian authorities haven't reported finding a severed foot since February 2019, the phenomenon remains fresh in the minds of B.C. residents.

Canadian artist Douglas Coupland, for example, recently sparked some backlash on Instagram when he posted an image of what appeared to be a decomposing leg.

In what can only be described as truly horrendous timing, Coupland posted the photo just hours before Sunshine Creek RCMP said that they were investigating human remains in the same area.

RCMP have since confirmed that Coupland's photo is unrelated, but Canadians were disturbed at the time.

"If you found this and posted a photo, I find that to be pretty gross," one person wrote.

View this post on Instagram

A post shared by Doug (@douglascoupland) on Jul 10, 2020 at 5:21pm PDT

Other B.C. residents, however, were shockingly blasé about Coupland's post on social media, evidently used to hearing about human remains found along the Salish Sea coastline.

"Doug, you do know that finding a left foot in a tennis shoe on a BC Coastline officially makes you more British Columbian than everybody else," one person wrote.

"Most BC thing I've seen all day," another person added.

Coupland told Global News that the timing of posting the image was just a "strange coincidence" and that the leg was part of an exhibition he put on two years ago at the Vancouver Aquarium.