It is a necessary item to defeating The Ghost Tree / The Tree Ghost.
In the original, It avoids the attack of pests before entering the classroom.
In the Remake, the intended use has changed unlike the Original. It is a final item to defeat the The Tree Ghost.
Korean name of this item in the game is "해충방지 스프레이"(Harmful Insect repellent Spray).
It is found in the Mountaineering club (or In the remake version, Hiking Club ) on the 2nd floor of Main Building, Section 1,Yeondu High School.
The club itself is locked and should be unlocked with the Classroom Master Key.
- The original Insect Repellent bottle has Sonnori logo on it, much like several things in the game.