What is the rarest hobby in the world?

Uncommon Hobbies Around the Globe

Some of the rarest hobbies in the world, such as corrosion casting, extreme ironing, and blood painting, are pursued by only a few individuals. The practice of corrosion casting, which involves creating resin models of blood vessels, and blood painting might put off potential enthusiasts due to their graphic nature. On the other hand, extreme ironing combines athleticism with a sense of adventure, making it appealing to thrill-seekers.