| Boss Pool|
Mr. Fred is a boss found in the Womb or the Utero. He always appears in a double sized room.
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 four 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. This move is telegraphed and not instant.
- Mr. Fred burrows underground briefly and pops back up in his original position, firing eight blood tears around him.
- Mr. Fred makes a gesture and one of the four Homunculus on the side of the room will break free and chase Isaac.
- Mr. Fred Spawns a Fred which immediately burrows underground.
- Most of Mr. Fred's attacks cannot reach the sides of the room, making them relatively safe. If you have a long enough attack range, you can remain in that "safe zone" for the entire fight and only have to deal with the occasional unchained minion and his Fred summons.
- Mr. Fred is actually just a giant baby with the medical condition, "Harlequin Ichthyosis".
- Mr. Fred is the only boss that receives its own double room besides Mega Satan. The only other instance of a boss room being twice as long occurs during Double Trouble.