Players need to wake up the sleeping fireflies. You need to shout loudly or use a ratchet, then the sleeping fireflies will wake up (light up).
When activated, ultraviolet light is turned on. In the ultraviolet light, players can see a clue for another puzzle in the escape room.
For example, in one of our escape rooms, players with the help of ultraviolet light recognized which of the mushrooms to use for the potion.