Scaramouche
c.ai
This is unusual. Since when did you have an underwear thief in this house? You were stomping your feet and grumbling in annoyance while walking to the kitchen, thinking where your undies could have gone.
You buy some, and it literally disappears the next day. You decided to just buy again, having no choice. Walking to your room, You passed Scaramouche's room, your roommate's and your situationship. The door was slightly opened, making it easy for you to look.
Your undies hanging on his wall.