Squid ink is a dark, viscous fluid produced by squid as a defense mechanism. The reason it stains for so long is due to its composition, which contains melanin (the same pigment responsible for the color of human skin, hair, and eyes), along with other proteins and enzymes. The melanin molecules are large and have a strong affinity for bonding with fibers, such as fabric or skin, making them difficult to remove. Additionally, squid ink is water-resistant, which means it doesn’t easily dissolve o