Rotten Freddy is an antagonist in Fredbear and Friends: Left to Rot.
Rotten Freddy appears similar to Withered Freddy from FNaF 2, but his suit is warped and distorted from age and a damp environment. Many of his joints are exposed revealing the endoskeleton beneath, his jaw is tattered and loose, and he still holds his signature microphone in his right hand. He appears to have the least amount of damage out of the four rotten animatronics. He also has maggots in his mouth, which is weird as the part they are on seems to be made of a plastic type material rather than a fabric.
Rotten Freddy is active during Test Room 02, along with Rotten Bonnie, Rotten Chica, and Rotten Foxy. He will begin in CAM 01 before roaming the facility and attempting to enter the player's office using the left vent. The player must check the camera for him and when he appears in the left vent, the ventilation must be shut off on Freddy's side to drive him off. Failing to do this in time will result in Freddy jumpscaring the player, causing a game over. The ventilation cannot be left off for too long as this causes the toxicity percentage to rise and will cause the player to pass out of it reaches 100%. Rotten Freddy will also occasionally appear in the player's doorway, but is harmless when doing so and will not attack.
- Rotten Freddy is presumably the same Freddy from the Training Tapes but damaged due to age and neglect after Fazbear Entertainment closed it's doors.
- Rotten Freddy's attack pattern of using the left vent is similar to his appearance in FNaF 1, where he would stand at the player's left door and play his music box before attacking after the power had ran out.