I think you've heard about the game "Baldi's Basics". And this addon adds one of the characters in this franchise. In his own way, he will add inconvenience and a little fear to your world.
The character you can now meet is called Test. He looks like a creature resembling a human, has a green jacket, black pants, white shoes and gloves. His main ability is to blind the player. If you see him, try not to get too close to him. Otherwise, your world will be plunged into darkness for a certain amount of time, you will be accompanied by a little pleasant melody, and the Test, leaving only your head, will teleport and be behind your back:
