A permanent marker is a writing instrument that is used to make marks that are difficult to remove. The most common type of permanent marker is a felt-tip PEN, which is also known as a 'Sharpie'. Other types of permanent markers include tattoos, scarring, and indelible pencils. Tattoos are created by injecting ink into the skin, while scarring is caused by cutting or burning the skin. Indelible pencils are made with a special type of graphite that is designed to be difficult to erase.