Final answer:
The Puppet, also known as Marionette, from Five Nights at Freddy's 2 disables your flashlight and vent lights when it enters your room, indicating you did not keep the Music Box wound up.
Step-by-step explanation:
The character that enters your room and disables your flashlight and vent lights in the second game of the Five Nights at Freddy's series is known as The Puppet (also known as Marionette). When The Puppet comes into your room, it signifies that the Music Box has wound down and you have failed to keep it wound up. This mechanic is central to the gameplay, where you must manage various tasks to survive each night.
Other characters known as animatronics also pose threats of their own, each with unique behaviors that the player must learn and strategize around to prevent being caught. Keeping the flashlight and vent lights working is crucial in monitoring and protecting against the advances of these animatronics.