Strobulb

The Strobulb is a flashlight tool which appears in Luigi's Mansion: Dark Moon. The Strobulb is required to stun some Ghosts as, unlike in the first game, shining light via flashlight is no longer sufficient to stun all ghosts in the game. Players need to charge up the Strobulb and unleash a powerful beam of light. The longer the charge, the greater the range. A fully charged flash will allow the player to stun multiple ghosts at once than an ordinary flash. Some ghosts wear sunglasses to protect them from the light; these sunglasses must be removed with the Poltergust 5000 before the flashlight or Strobulb is used. When charging the Strobulb, the actual light coming from the flashlight decreases as it starts charging, and while it is fully charged, a small circle is seen at the source. Unleashing it creates a powerful beam of light, with small light particles at the end of the flash.

Luigi gets it in the first mission of the game when he enters Gloomy Manor and finds out two Greenies have it. The Strobulb is activated using.

Trivia

 * From a development and control standpoint, the Strobulb was most likely added to the game due to the player's lessened control over Luigi's flashlight due to the Nintendo 3DS' lack of two control sticks like the Nintendo GameCube controller.
 * In Scarescraper, the player's Strobulb when charging will glow the same color as the color they're wearing.