This mutant mushroom is the muscle of this area. It is joined in battle by the regular Walking Mushrooms that you have already come to fear. The first two mushrooms often get help from their sporlings.
Shrooom! is the fourth Sanctuary Boss in EarthBound. It guards the Rainy Circle, the fourth Your Sanctuary. Shrooom! does not have many damaging attacks, so it mostly relies on causing status conditions, such as the dangerous Mushroomization. Once Shrooom! is defeated, Ness and his friends may enter the Rainy Circle and record the fourth piece of the melody on the Sound Stone.
Jeff passes through Shrooom!'s cave on his way to join up with Ness and Paula in Threed, but he is unable to use the power of the Your Sanctuaries and therefore cannot fight Shrooom!.
The EarthBound Player's Guide erroneously states that Shrooom! is accompanied in battle by "Walking Mushrooms" when in fact it is fought alone.
Alignment:Lawful Evil (Sanctuary Guardians are under the influence of Giygas and have stole Ness' sanctuary locations)
Threat Level:Metropolitan Threat (Sanctuary Guardians pose threats over entire towns they're near and are the boss of the entire dungeon area, which are normally multi-leveled cave systems)
Intelligence:Genius Intelligence (As the Shrooom! has drained the energy from the your sanctuary location and has shown to use PSI from it, they should naturally be this intelligent)
↑"PSI is a mysterious and useful power that can replenish your energy or even assist in your transportation needs. Using PSI will deplete your PP." MOTHER 3 Memo Description
↑A miraculous stone that enables you to "concentrate" without using your own brain. This is accomplished just by your keeping this item. This is great because if you can't concentrate, you can't use PSI.