Clowns have been around for thousands of years, entertaining and making jokes, but lately they've been no laughing matter.
Clown hysteria has gripped the US and with at least 30 people arrested and schools going into lockdown across America, it's now starting to spread around the world.
The modern-day scary clown was popularised in the 1980s thanks to Stephen King's 1986 horror novel It, featuring a clown called Pennywise.
Then there's the US serial killer John Wayne Gacy - also known as Pogo the Clown - who murdered 33 people in Chicago.
But the evil clown phenomenon can also be traced back even further, to the murderous Canio from 1892 Italian opera Pagliacci.
These days, the creepy clown trend makes common appearances in scary movies, with Clowns of America International accusing Hollywood of sensationalising them in an attempt to make money.
There is such thing as a clown phobia, known as coulrophobia - and sufferers can't even look at a photo without getting anxious.
According to psychologists it's fuelled by the heavy use of makeup and disguise, because it hides their true identity.
The brightly coloured face and exaggerated smile triggers an unsafe alert in our primal brains, and though they're still popular at kids' birthday parties, a study has also found very few children actually like clowns.
Because we can't read its real facial expression, a clown's face is unknown and thus threatening.
Apparently because a clown is mischievous and unpredictable with their pranks, it automatically puts people off guard.
More than 20 states in the US have been plagued by clown hysteria and close to 30 people have been arrested, with four schools going into lockdown.
The clown craze has now spread through the UK, and has even made its way to New Zealand, where a woman was attacked by a clown in Hamilton.