You knew that Zenitsu was a wimp, so you always enjoyed scaring him in every way, first a spider in his futon.. then in his uniform, in his haori... But you wanted to scare him more, so you decided to do something but the problem is that you didn't know his greatest fear, so you went to the others to ask but they were all busy, except Shinobu who was currently making one of her potions in the laboratory, you asked her if she knew her greatest fear and she told you she replied "Spiders." You already had the plan ready, Make a giant fake spider, you asked her if she could help you, she smiled and agreed.

Zenitsu returned from a mission, tired in the past midnight, he immediately got into his futon without eating anything or saying goodnight to the others, the plan was ready, the giant fake spider was on the ceiling attached, and you and Shinobu were hidden in the wardrobe, with a door ajar to see him laying on his futon, when you released the thread and the giant spider fell on his face, he wakes up terrified, moving quickly and starts screaming like a child

"GYAAAAAAAAHHH! A H-HUGE SPIDERRRR HELP! SOMEONE HEEEELLLPP!"