Any illness can be frightening, but some are arguably scarier than others. For example, those that cause great pain or physical deformation, or whose origins are still not completely understood, can strike terror into the hearts of even the bravest of men. In a video produced last year, the team at They Will Kill You compiled a list of 10 of the most horrific human diseases. View with discretion.

Noma, Cancrum Oris

This horrible infection causes ulcers to form in the mouth or on genitals. Eventually, the ulcers wear down the tissue until it no longer exists, leaving the the patient disabled and with a 90 percent chance of eventually dying from their infection.

Emycetoma, Madura Foot

Yet another gruesome infection, this fungus usually affects the feet, causing swelling, and is eventually disabling.

Read: 3 Of The World's Most Terrifying Illnesses — And You Thought Ebola Was Bad

Complex regional pain syndrome

As you’ve likely guessed from its name, this illness causes extreme pain due to the breakdown of the nervous system. Eventually, the pain can get so bad it leads to mental health issues, such as depression and anxiety.

foot This fungus usually affects the feet, causing swelling and eventually disabled. Photo Courtesy of Youtube Screenshot/ It Will Kill You

Leprosy

This infection causes inflammation of the skin and eyes, and can eventually lead to the gruesome loss of body parts and eyesight.

Filarial worm, loa loa worm

This parasitic worm likes to live in the eye and is the second leading cause of blindness worldwide. When the worm infects other areas of the body it causes a condition called elephantiasis.

Vibrio vulnificus

This infection is mostly caused by eating raw shellfish or having an open wound when swimming. It can lead to a range of symptoms such as vomiting, intense diarrhea, blistering dermatitis, and severe abdominal pain.

Pica

Pica is an inexplicable desire to eat non-food items not caused by mental health conditions. Depending on the type of item you eat, the condition can lead to everything from severe infection to death.

Fibrodysplasia Ossificans Progressiva (FOP)

In FOB, the muscles, tendons, and connective tissue slowly turn to bone, eventually leaving a patient completely unable to move.

Clarkson’s Disease

In this rare disease, plasma leaks from the blood vessels causing the patient to swell. What’s more, doctors still have no idea what causes it.

Elephant Man Syndrome

The elephant man, born in England in 1862, grew thick, lumpy skin that resembled that of an elephant. Still, over 100 years after his death, scientists still aren’t sure exactly what lead to his horrific deformities.

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