Sewer is just a plain room that has similar lighting to real room.
Inisde it, is Angry Figure, witch will then rise from hell and start moving to the staff are, the meat freezer and then the office.Crystal Cursed Doll will start in there too, then moving to the staff area, meat freezer, lounge, and then the office. D.O.N.A.L.D will get outside of the black hole and go to the staff area, Character prep 2, the roof and then the office.
Something unknown can ben very rarely appear in the Sewer. The Sewer Is Rusted Over The Disastrous Day. Some suits can have 0.2353% or a rare chance of appearing inside The Sewer.