Millepora squarrosa, also known as Millepora striata, is a species of fire coral that can be found in the Caribbean Sea as well as in the West Atlantic. They have a smooth surface covered in tiny pores from which polyps protrude. They can reach up to 5 centimeters in height and can range from brown or tan in color with slight purple or red tints. It is commonly known as "box fire coral", which refers to its box-like structure and the stinging sensation felt when touched with a bare hand.