If you stand at the main entrance of the mansion in the daytime and slowly turn your camera angle, you can see a whitish figure right beside you.
In the Cellar, if you hit the hanging lanterns on the ceiling, you can sometimes hear a woman grunting.
Sometimes if the player hits the altar long enough, (with a firebottle) sometimes a man can be heard screaming, "Hey!" but when the player turns around, there is nobody there. Some of this may be explained by the fact that sometimes people will go through Tumbleweed like any other town.
When the camera angle changes or a player walks from room to room in the mansion, the lights often flicker.
All of the "dirt mounds" of the graves in the churchyard are target-able in Dead Eye, although only Elenora Riddick's has so far been found to be destructible, albeit empty.
A large number of bats can be seen flying out of the mansion at around 6:05 P.M. then return at 6:00 A.M. These bats can't be killed or even shot. They can also be found in Thieves Landing and possibly in some other locations.
The walls on the first and second floor of the Mansion change color randomly and slowly.
All day, a dog can be heard barking but no dog is seen. If the player follows the barking of the dog they will find the source of the barking is the cemetery. This same sound can be heard in Beecher's Hope after the game has been completed.
There is a coyote on the hill across the road from the church—the hill with a windmill on top of it. With some patience, it is possible to get to the top of the hill and find the coyote. This is NOT the cause of the Hellish dog barking - as mentioned before it is traced to the cemetery, not the hill. Kill the coyote and you'll still hear the demonic barking.
There are horses in a barn when you first arrive there. The next day they may be gone. When they are gone and you travel up to the windmill, you will find a very skinny horse, looks to be near death. This horse has bad stamina and is very slow. This is all that remains of those horses.
The sound of footsteps and people talking is due to the fact that there are people inside the mansion in the first floor. However, it is impossible for the player to enter the room where they are without triggering an execution animation, which allows the player to glitch through the locked door. This may be due to the player not triggering the hideout or the conditions that release the code locking the doors to the enemies in the mansion. This could be the cause that some players have heard footsteps and people talking. A variety of NPC's consistently mill around and greet each other in the locked room; this is confirmed and the video can be seen here . (evidence begins at 8:25)
After killing the lights in some buildings, exiting the building will make the building appear like it is lit up again, while entering will immediately darken the building. However this works with any building in the game.
At about 6pm (Red Dead Redemption time), footprints appear on the stairs to the cellar in the mansion. If the game is paused, they can clearly be seen.
Footsteps and bodiless voices yelling at you to "watch where you're going" may be found in the Tumbleweed Mansion's cellar during the Treasure Hunter Challenges if you haven't alerted the criminals in Tumbleweed.
Rabbits can be found sitting in some of the rooms of the mansion and won't move if the player goes toward them. They can still be killed and skinned.
On the second floor of the Saloon, one curtain is being blown by the wind while the other curtain remains perfectly still.
On the first floor of the saloon, a lantern in the corner is floating but you can still destroy it.
On the first floor of the saloon, if you look in the corner quickly, you'll see a white mist. Even if it is in the day.
In the middle window of one side of the church in the bottom right frame appears to be a Satanic looking face. It is hard to make out at first, but is definitely there if one gets the view right. Whether this is a common window texture that coincidentally appears like this or not is currently unknown.
He, again, appears on the window closest to Lincoln Crenshaw's gravestone. Can only be seen through a scope.
As well, there are rumors about The Devil appearing in the church. There are many theories on how to make him appear, ranging from staying in/near the church for extensive amounts of time, to waiting till a certain time of day, to "hitting" the altar (with a fire bottle usually). These are unconfirmed, at least for the PS3.
At 4:03 in the cellar a faint "How do you do?" can be heard. This is proven on many YouTube videos.
Around 8:00PM on Saturday (game time) in the cellar, a supernatural, eerie "ghost light" can be found flashing, glowing a whitish-green color. It's more noticeable when the doors are closed.
The saloon's clock works. Given the neglect of Tumbleweed, this barely seems possible.
Another rumor in Multiplayer that you could see a ghost in the basement or cellar, this remains a cold hard mystery if you could see the ghost in Tumbleweed.
When standing right next to or behind the alter in the church, if you shoot the front door open, then slowly swing the camera around you in a set of 2 full 360 rotations (one after another), when you come back to facing the church door after the second full rotation, it will have closed by itself.
If you turn up the volume very loud. Footsteps can be heard in the mansion. However this may just be the curtains at the top windows of the mansion that are sometimes blowing about.
Rarely, a NPC will say " Did you hear the screaming at Tumbleweed last night?"
Sometimes, at night, if the player should walk into the upstairs room at the back of the Mansion, a ghostly figure of a woman will be sat down in a chair in the corner. When the player catches sight of her, she casually gets up out of the chair, walks a few steps, and fades away. This can be done both on multiplayer, and single player.
From the Southern end of town by the mansion, one can see Ojo Del Diablo, located in Mexico.