The person renting it out, Jason, doesn't want to be identified as he's not allowed to sublet his one-bedroom, one-bathroom unit.
"I wish I could find some other name for it because I don't really care about Harry Potter that much, I'm much more of a Lord of the Rings guy. But uh - it's just a place to sleep," Jason said.
He said rent increased in August to nearly $1,800.
MORE: Would you pay $700 a month to sleep in a pod? Tech founders are doing it to afford San Francisco
Would you pay $700 a month to sleep in a pod? Tech founders are doing it to afford San Francisco
"I paid the first increase rent month and realized with a little bit of math that in about 11 months I would be down to my tent or my car, cause my savings would be gone," Jason said.
Now he's resorting to finding a roommate for this space that is roughly only 3 by 10 feet.
Jason posted an ad on Craigslist titled "$250 Harry Potter cubby for very cheap + light chores."
"It's about what I need to afford the rent, I'm not Blackstone I don't want to charge people for profit, I just want to be able to not live in a tent," Jason said.
The Craiglist ad has been posted for a month and on November 1st, his first potential roommate will visit.
MORE: Bay Area embracing ADUs amid housing crisis - are they worth the investment?
Are ADUs worth the investment in the Bay Area?
Jason says the renter wouldn't just have access to the Harry Potter cupboard. There are no restrictions on cooking, internet, kitchen, bathroom or gaming space, unlike other ads for rent.
"One of the places I looked on Craigslist for $600 was someone's partitioned-off living room with sheets and they had restrictions on bathroom usage like you could only go between 6 and 7 a.m. or 8 and 9 p.m.," Jason said.
Jason's ad also mentions that he'd like to rent it out to a "nice nerdy gamer."
"It's just sort of a culturally shared experience that goes between race and creed and religion," he said. "It could be rock collecting or picking up dinosaur bones, as long as there's some sort of nerd or geek I'm ok."