They replace the Grey Child seen in the North American version; the reason behind this is because the Grey Children resembled real-life children too much, and then, as a result, the Grey Children were not included in the European and Japanese versions.
Mumblers are small creatures with a giant hole where the face should be. They are reddish-brown in coloration and have three humongous claws that protrude from their arms. Their name is derived from the mumbling sound they make when approaching the player.
Their claws serve as fingers, which can be used to deliver incredibly strong attacks. Their method of attack is similar to that of Grey Children, in which they jump onto their victim's legs, immobilizing them, while clawing at them at the same time. Though they move slowly, they make up for it in strength.
The Mumblers take on a dark image of the small menacing animals and demons from fairy tales that Alessa Gillespie used to read frequently as a child.
- Mumblers have a varying role in the game, depending on the regional version being played. In the original version, Mumblers only appeared in the sewer in the later part of the story. The PAL version is radically different, with the Mumblers replacing the Grey Children in every part of the game. This was due to the Grey Children's resemblance to little children, which was chosen to be censored due to laws regarding the killing of children/child-like resemblances in a video game.
- A sketch of a Mumbler appears in Silent Hill: Revelation, likely as a cameo, although they never appeared in the film series.