Blacklights can be toggled on and off by the player. When in use, the blacklights will illuminate a cone-shaped area in front of the player in purple UV light. Unlike other light sources, the UV light from a blacklight does not anger Squiddles. While a blacklight is turned on it will slowly lose charge until it runs out. Upon inserting a single battery, the blacklight will be recharged and can be used for 24 more seconds.
Obtainment
Blacklights can be found in item spots inside of the Hadal Blacksite. Blacklights can also be purchased from Sebastian's Shop for 400 research. Blacklights can also be bought in the Pre-Round Shop for 100 kroner if the player has the "We Die in the Dark" Achievement
Notes
Blacklights have a shorter battery life and weaker light output compared to other light sources, making them inefficient for regular use.
The UV light emitted by a blacklight may be hard to see in certain rooms.
Blacklights are reusable and are not removed from the player's inventory after running out of charge, instead being rendered unusable until recharged.
While the light from a blacklight does not anger Squiddles, other player interaction methods such as standing too close will still cause them to attack.
Gallery
The player holding a Blacklight in a dark room.
The player safely shining a Blacklight at a Squiddle.