You need to go to the rent house to see a boot with a worm in it. You need to follow the instructions to get the key. Make sure you have a paper and pen to write the code.
no.
There's no secret door in the Puzzle Palace. There's one in the Underground Disco but nobody can get through it.
There is a scary looking door in the Underground on Moshi Monsters, to the left of the entrance to the Disco. This door was part of Super Moshi Season 1 Mission 5 "Pop Goes the Goo Goo". During the mission you have to unlock and open the door to find the secret C.L.O.N.C. lab.
You have to be a Moshi Member.
There's a big scary door, with a large chain and padlock to the left of the Underground Disco on Moshi Monsters. This appeared in the Super Moshi Mission "Pop Goes the Boo Boo". In the mission, we find out that there's a secret C.L.O.N.C. lab behind the door.
You have to be a member. Only members can go in the underground disco.
There's a guarded door in the Underground Disco that cannot be opened. What is behind it remains a mystery.
No one can open the other door in the Underground. It is just part of the scene.
I'm not sure can any one help?
No, there currently (January 2015) is no fire door on Moshi Monsters.
There is a Candy Cane Door on Moshi Monsters that you can buy at the DIY Shop.
You can not get in the scary door in the Underground on Moshi Monsters. It is there because it is part of a Super Moshi Mission.