Mr. Fred is a giant baby with a medical condition Harlequin Ichthyosis. He has cracked red skin, bulging pupilless eyes, and round lips with four visible teeth. His torso is always visible while his lower part is in underground.
Mr. Fred stays in the center of the room throughout the whole fight, occasionally burrowing underground for brief periods. He will not chase the player.
Mr. Fred has a number of different attacks.
- Mr. Fred shoots 4 long-range blood tears in the cardinal directions around him. These tears leave red creep and will burst at the end of their range into a larger pool of creep.
- Mr. Fred burrows underground briefly and pops back up in his original position, firing 8 blood tears around him.
- Mr. Fred makes a gesture and one of the 4 Homunculus on the side of the room will break free and chase Isaac.
- He can spawn Fred.
- While his appearance being based on Harlequin Ichthyosis, Mr. Fred's appearance bears some resemblance to the Harlequin Baby.
- He is one of the few bosses not to have any champion variants.