Friendly Ghost

Friendly Ghosts are characters in Mother 3, being a friendly variation on Stinky Ghosts. They enjoy eating Rotten Eclairs, or any other moldy, unsavory food, despite it passing right through them.

In Chapter 2
Friendly Ghosts reside in Osohe Castle, spending their entire lives partying in one of the upper floors. They all hate the Ghost Knight, leaving a sign thanking the player for defeating him. A ghost on the first floor owns the Ghost Bazaar, which exchanges items for Rotten Eclairs. During the latter half of Chapter 2, which takes place concurrently with Chapter 3, the ghosts are forced into a single room, where they complain about how cramped it is; it is at this point that the Ghost Bazaar is closed down.

In Chapter 3
During Chapter 3, the Pigmask Army forces most of the Friendly Ghosts into a single room.

In Chapter 4
During Chapter 4, the Friendly Ghosts' party is over, being tired after partying for the last three years. A post on the Tazmily Village Central Message Board is written by a Friendly Ghost, which asks the citizens of Tazmily Village to die quickly because they are slowly losing friends in Osohe Castle.

In Chapter 7
In the Chimera Laboratory, trying to enter the ladies' bathroom will display a ghost for a moment, and a ghostly laugh is heard. Each time this is done, another ghost is added, up to a maximum of four ghosts. After the fourth, it resets the amount of ghosts to one.

In Chapter 8
Inside the Empire Porky Building, all of the Friendly Ghosts from Osohe Castle can be seen crammed inside a bathroom stall by the Pigmasks.

Memo
These guys come to life almost every night to gather for a "grave" party. Just let them be if you can help it.