Ultimate Custom Night is a standalone horror game developed by Scott Cawthon and released in 2018. It is part of the Five Nights at Freddy's (FNAF) series, which centers around a fictional restaurant called Freddy Fazbear's Pizza, where animatronic characters come to life and attack the night security guard.

In Ultimate Custom Night, players can select from a roster of 50 animatronic characters from the previous FNAF games, each with their unique abilities and behaviors. The game takes place in the security office of the restaurant, where the player must survive the night by monitoring the animatronics and keeping them away from the office.

The game features a customizable difficulty system, allowing players to adjust the AI levels of each character to create a unique and challenging experience. Players can also set up different challenges and scenarios using different character combinations.

Ultimate Custom Night offers various mechanics and gameplay styles, including point-and-click, puzzle-solving, and reflex-based gameplay. The game's horror elements include jump scares, tense atmosphere, and creepy sound effects.

Launch the game and select "Play" to start a new game.

Choose the animatronics you want to include in the game. You can select up to 50 characters from the previous FNAF games, each with their unique abilities and behaviors.

Set the difficulty level for each animatronic by adjusting their AI levels. You can create custom challenges and scenarios by selecting different character combinations and difficulty levels.

Once you've selected your characters and difficulty settings, the game begins in the security office of the restaurant. You must survive the night by monitoring the animatronics and keeping them away from the office.

You can monitor the animatronics using various tools, including cameras, lights, and doors. You must manage your power supply, which depletes as you use these tools.

The animatronics will move around the restaurant, trying to reach the office. If they get too close, they will attack and kill you, resulting in a jump scare.

The game features different gameplay mechanics, including point-and-click, puzzle-solving, and reflex-based gameplay. You must use your wits and reflexes to survive the night and make it to the end.

The game features multiple endings, depending on whether you survive the night or not. You can replay the game with different character combinations and difficulty levels to unlock new endings and achievements.