A woman who slapped a beetle that landed on her face was horrified when its bizarre defence mechanism kicked in and it sprayed boiling water over her cheek as it died.

It turns out that the woman was a victim of the famous “100-degree poisonous fart” of Pheropsophus jessoensis, which is less formally known as the Asian bombardier beetle and known less formally as the “fart bug”.

They have the incredible ability to eject a hot and noxious chemical spray from the abdomen in a violent explosion that instantly kills insect rivals, and can cause serious damage to other large animals including rodents and even people.

In addition, the superheated liquid reportedly smells incredibly bad, hence the reason it is often known as the “fart bug”.

The unnamed woman who was injured while she was at home in the city of Yixing, in China’s eastern Jiangsu Province, said she felt the bug on her face and, without looking at it, had instantly used a hand to slap it away in the incident on 13th June.

She said: “I decided to walk home and when I got there I sat down on the sofa to look at my mobile phone, when I suddenly felt the bug on my face and swatted it away.”

But she was stunned when she felt a burning sensation on her face and ended up hospitalised to be treated for the injury.

She was a victim of the bug’s incredible defence mechanism, which allows it to eject the boiling liquid from its rear using a reaction between two hypergolic chemical compounds, hydroquinone and hydrogen peroxide, which are stored in two separate reservoirs in the beetle’s abdomen.

When the two solutions come together, catalysts cause rapid decomposition of the hydrogen peroxide and the oxidation of the hydroquinone generates intense heat that brings the liquid to near boiling point.

She said: “I couldn’t believe it when I looked in the mirror and saw huge blisters appearing on my face. It looked just like it would have if I had been burned, and it turned out that was exactly what happened.”

She said medics had helped her to understand what had happened after she took the dead bug with her to the hospital where she was treated as an emergency patient.

Zhou Zhigang, deputy chief physician of surgery at Yixing Traditional Chinese Medicine Hospital, said: “If an unknown insect lands on your body, use a fan or clothing to gently brush it away, or blow it away gently with your mouth.

“Do not slap it directly on exposed skin. If the skin is accidentally splashed with acidic venom, immediately rinse with soapy water to neutralise the toxin and go to the hospital for treatment in time.”

Online commentators like ‘User 0226622’ said: “I also encountered this last year, and the scar on my face took half a year to heal.”

And user ‘Clouds Reflected In Water’ said: “This smell is still very stinky.”

While the user ‘Na Is A Fairy’ said: “It’s quite powerful!”