The flashlight is an item given to the player in Tattletail.
Overview
Appearance
The flashlight is a large flashlight that, instead of using standard batteries, uses magnetic induction to build electricity. When the player first receives it, it glows green, but from then on it glows a cyan-ish color.
Gameplay
The player receives the flashlight on December 21, 1998. It is used to see in the dark when the lights are out.
Tattletail is afraid of the dark, and will emit noise when in the dark too long. The Flashlight counters this.
The player must shake the flashlight by holding the right mouse button in order to power it up. However, this creates noise, and will attract Mama to the player. Looking at Mama directly will cause the flashlight to go out.
Golden Flashlight
The Golden Flashlight is an upgraded version of the stock flashlight, featuring a longer battery life.
In the Secret Ending, after getting Tattletail's tag, you will see a small box on the ground. Open it, and you will find the Golden Flashlight.
The Golden Flashlight.