Trepanning, the act of drilling a hole into your skull and allowing it to heal over, is one trend starting to gain more traction on the underground body mod scene.

Body mod expert and the man responsible for promoting the "Bagelhead" movement, Ryoichi Keroppy Maeda, gave Daily Star Online his take on the strange phenomenon.

The process dates back more than 8,000 years, but could still be a bridge too far for extreme modding, he said.

Keroppy said: "Trepanation is simply the first step. I think new modification of the brain of the skull is coming in the future.

"Humans started trepanning millennia ago. Why would they do this? I've been told it expands your mind. Elevating your consciousness.

(Image: RYOICHI KEROPPY MAEDA)

(Image: RYOICHI KEROPPY MAEDA)

"It's still considered extreme modification in today's scene, it's mostly done underground because it's illegal in some places."

Modding itself is already advancing at an alarming rate, with enthusiasts now exploring the idea of bio-hacking.

This entails anything from implanting glowing lights under your skin, to having magnets surgically placed into parts of your body.

Keroppy is notorious for having a very liberal view of modification, having travelled the world to meet people with unusual and extraordinary mods, but even he has concerns over trepanning.

(Image: RYOICHI KEROPPY MAEDA)

"I don't recommend people try this. It's a very risky procedure," he said.

"People I've met with holes in their head seem happy. They enjoy it. But I certainly wouldn't recommend it to everyone."

He advises people to embrace the "Bagelhead" instead – which involves injecting saline under the skin of your forehead causing it to swell.

By placing a thumb in the centre of the swelling pocket in the forehead, the bagel shape forms.

(Image: RYOICHI KEROPPY MAEDA)

he process generally lasts only one night, and according to Keroppy is completely harmless.

In his home country of Japan, where body modding is becoming very popular, trepanning is banned.

He explained the people there have become very conservative after the earthquake and nuclear disasters.

Those looking to push the limits of modification have to choose between going underground and embracing a very extreme, polarised movement, or waiting for more liberal laws currently being fought over in the courts to pass.

(Image: RYOICHI KEROPPY MAEDA)

But Keroppy insists the process is gaining huge popularity, with many raving over its depiction in comic books.

In order to explore the concept, he drilled a hole in a deer skull himself, which put him off trying it personally.

He added: "Trepanation has definitely opened my eyes to to new ideas and trends within body modification.

"Both in ancient history and as modding turns to the future."