Maws are pale severed heads that float with empty, bleeding eye sockets, and a wide open mouth with a few teeth inside. They are commonly found in The Caves, The Depths, and their alternate floors. They can also be spawned by Mr. Maws.
Maws are similar to Horfs, but are upgraded; in addition to shooting blood shots at Isaac like a Horf, they slowly float toward him. Maws take a lot more knockback from Isaac's tears, which allows them to unpredictably bounce around the room.
Champion varieties of Maws fire much larger blood shots.
Red Maws have a pinkish-red head, and their mouths are stitched shut, removing their shots; Instead of firing blood shots at Isaac, they float towards him at a higher speed than regular Maws, exploding into a plus pattern of blood shots when they die.
Red Maws fire larger blood shots upon death if they're champions.
Psychic Maws were added in the Wrath of the Lamb DLC. They will rarely replace regular Maws/Red Maws. Both their eyes and mouth are stitched shut, with a large third eye burning with purple flames on their forehead, which is crying with blood. They behave exactly like other Maws, but fire large, purple homing shots and have increased health, thus making them a much greater threat. They also have an Eternal Fly orbiting them, which can block Isaac's tears.
- The appearance of Psychic Maws resembles Isaac with the Spoon Bender item.