Stalburg Mushroom Virus (SMV) also known as Fungal Desease in public knowledge, is a bioweapon reportedly researched by S.N.W. One of the main researchers was Xeander Berg, who became infected with it. Jeff Walter was concerned about what S.N.W. was going to do with the virus in a letter to him.
An S.N.W. investigation by Sven Olsson describes SMV as "a kind of disease that slowly kills the target." It can also cause "strong hallucinations and strange and violent behavior." The origin of the virus seems to predate the bunker itself, since the document says "they found something" while building the bunker. It mentions everyone left the bunker because of some kind of leak that caused immediate evacuation. All the SMV information was sold at some point to an unknown party.
Since the virus has spread all over the city, shrooms are overused by residents in Stalburg. The goverment has planned to clean the city from shrooms and relocate every person diagnosed with SMV to quarantined area in Obenseuer. Most of city has been cleaned, causing overpopulation in Obenseuer.
The shrooms seem to transmit their effects via spores since just being near them or smelling them will cause the effects of the specific colour.
Green shrooms are the most abundant type of shrooms found throughout Stalburg, and will kill you if you go near them for too long. They are frequently used as hallucinogenics by the residents, especially in Turnip Hill, where there are drinks, food and even an entire cake centered around these green shrooms.
In Open Sewer (game), there are three types of green shrooms: green, greener, and greenest; only the latter two giving you SMV (and decreasing your health). There is also "Pure green Mushrooms" which are obtained from the pharmacy and carry no SMV.
The only places in INFRA where blue shrooms are around the UGU in the stormdrains and in Kevin J. Herts's apartment in Turnip Hill in a tank, where Kevin notes that the blue shrooms have healing powers and can in fact cure people of SMV, although he notes it is unknown if there are any side effects from them.
In Open Sewer (game), blue shrooms reduce your SMV progression rate and heal you by 10%, but are extremely hard to obtain.
The only place in INFRA where red shrooms are found are in tiny amounts on the ground where Xeander Berg and Eric Kleinmann died. It's theorized these shrooms are a byproduct of the green shrooms (SMV) consuming a human body.
It's also worth noting the "special coffee tin" that provides the Mörkö effect at the Mulex CoPan Coffee Machine has a red lid, which suggests red shrooms have a much different hallucinogenic effect to even summon Mörkö, and the special coffee itself is red.
Orange shrooms can be found in the mines after powerstation2, and they are theorised to make people go crazy (start thinking about statues and stuff).
In Open Sewer (game), orange shrooms hurt you by a large amount, but don't increase SMV much. They also actually increase your depression and alcohol much more than green shrooms.
In a page from the "Mushroom Co. Research & Development Dept." notebook, the shrooms seem to be killed by cold temperatures. It is mentioned the "green glowing shroom part" is gone then. When Antifreeze was poured on the shrooms, they grew bigger, but still didn't survive the cold.
- 1st day: Mushrooms growing on body
- 18th day: Mushrooms growing through skin
- 25th day: Weakness, unable to walk, memory loss
- 33rd day: Complete infestation
A folder by S.N.W. with some information about SMV