Mother Mushroom is the main antagonist in the episode "Mama Said", and is the result of many smaller mushrooms fusing by unclear powers.
Mother Mushroom is a giant mushroom with a mustard yellow color on its top and a lighter yellow color on its underside. It has multiple, smaller mushrooms of varying earthy tones growing on its top. It has a hole where its stalk should be, where a tentacle is seen coming out after Finn compliments it, and has a giant eye at the end with ten long eyelashes. Mother Mushroom turns pink with a white tentacle if it's enraged.
- "The Light Cloud" (flashback, cameo)
- The Mother Mushroom is somewhat reminiscent of the Mycon alien species from the PC game Star Control II.
- Both are hive-mind mushroom creatures that largely spout facts about itself in a masculine voice that's deep but not unfriendly.
- Both seem very interested in growth and spreading spores to a point where any non-mushroom creature is attacked after minimal provocation.
- Both can be distracted by beneficial acts – discussing new homeworlds for the Mycon, and giving compliments to the Mother Mushroom.