What is a ink sack?

An ink sack, also known as an ink sac, is a small gland found in certain species of cephalopods such as squid and octopuses. It is responsible for producing and storing ink, which the animals use as a defensive mechanism against predators. The ink is released into the water to create a dark cloud, which confuses predators and allows the cephalopod to escape. In some cultures, ink from the ink sack was traditionally used for writing or drawing. In cooking, the ink from the ink sack of squid is used to give dishes a black color and a distinctive flavor.