The Lonesome Ghosts are quite mischievous of playing tricks or scaring trespassers. They reside in an old manor, where they evidently receive few visitors, resulting in boring and lonely nights for the ghosts (hence their name). Their names are: Jasper, Grubb, Boo and Moss.
One night during the winter, the ghosts were alone in their mansion (called the "Old McShiver mansion") complaining about the fact that there's absolutely no one left to scare. Soon enough one ghost finds an advertisement in the paper about a ghost-hunting company called the Ghost Exterminators. They call with the shortest ghost disguising his voice, claiming their home is being haunted. The exterminators Mickey, Donald and Goofy head to the mansion, but are locked in and tricked, scared, and teased by the ghosts; Mickey chases a ghost upstairs but is locked in a room which becomes flooded with water, Donald is smacked with a wooden board and spat in the face by a ghost, and Goofy gets stuck inside a dresser and accidentally pricks himself with a pin. Eventually, the trio accidentally crash into barrels of flour and molasses, giving them the appearance of ghosts. The Lonesome Ghosts, absolutely horrified, are scared off and they escape the mansion and run outside.
They make very few cameos in the series and joined the other villains during the hostile take over in Mickey's House of Villains. Their debut short was also featured in the film. They also appeared in the episode House Ghosts by scaring Pete and pulling his underwear.
The ghosts (as in this game they are referred to as "the Ghosts") are minor characters in the game in which they seek Mickey and/or Minnie to have them stop Baron Pete since he kicked the ghosts out of their home in the 3rd level. They also appear at the end of the game to congratulate the player on defeating Pete and they join Mickey and the gang at the circus after Pete was defeated.
Since the Mad Doctor arrived in Lonesome Manor and the Pipe Organ went out of order, the Lonesome Ghosts settled into Bog Easy in the half-sunken Mark Twain Steamboat in the bayou on the outskirts. Mickey can choose to either help them with pranking the locals or helping the locals overcome their fears of the ghosts. If Mickey fixes the Pipe Organ while visiting Lonesome Manor, the ghosts will return home and give Mickey one of the missing pieces of Animatronic Donald as a reward.
The inclusion of the Lonesome Ghosts in the Epic Mickey series and their connection to Lonesome Manor was inspired by early drafts of The Haunted Mansion featuring the Lonesome Ghosts in some capacity, with a "Lonesome Ghost" being proposed as a potential host for the attraction.
In the Epic Mickey series, multiple Lonesome Ghosts appear throughout both games and with different names, including:
Ian: He acts as the "self-appointed caretaker of Blot Alley and the Spatters" (described by Gremlin Gus) in Epic Mickey 2.
In Disney Tsum Tsum, the Lonesome Ghosts appear as a non-playable Tsum and could be fought as a boss during the Mickey's Anniversary Film Collection event. They are represented by one single Tsum, and, unlike other boss Tsums that sometimes move around the screen, this Tsum disappears and reappears on a different location of the screen.