A New Zealand student described how they arrived home on Saturday to find the floors covered in $20 and $50 notes and no one else home.
Posting on Reddit, the student says neither flatmate had been home since 2 o'clock and couldn't figure out how all the cash had appeared on the floor.
According to the student, all flatmates are students and "work student type jobs".
"Very confused at the moment and wondering what I've walked into," the Reddit user said.
The person added that, other than the money scattered all over the floor, nothing in the house was amiss.
The post was first published on Saturday and has received dozens of comments from others trying to figure out where the money could have appeared from.
One Reddit user who claims to be a "NZ cop" suggested taking the money to the local police station.
"I know it might not be what you want to do, but I would pack it up with gloves into a clean plastic bag and take it to the local station. If no one claims it, then it's all yours. If it's from a serious crime, you will lose it sadly but it might help to hold some dero accountable.
"If it is from some dodgy dealings then you will be covered if they come back and try to tax you for it both; you can happily report it if someone come to collect, and say that you don't have it, but the po po do. If it is dodgy they won't exactly go in and say that they lost all their drug money, so you will probably end up keeping it if that's the story [gotta prove it's proceeds of crime]," the person said.
"At the end of the day, just do what you need to do to feel comfortable with the decision. But make sure you cover your a** and don't do something that could get you hurt, people do stupid s*** for money."
A number of commenters suggested it could be drug money.
The poster said they were leaning towards not going to police just yet.
"I'm leaning towards [calling the police]. Just thinking of if it's all legit I'd be pretty f**ked off if a flatmate called the police if it was mine," they said in a comment.
A number of Reddit users also believe the post might be fake.
"I don't wanna be that guy, but ima be that guy and say this is fake," someone said, with others pointing out that the poster has had a Reddit account for 10 years but has only posted twice.
It is not known where in New Zealand the flat is located and the poster also didn't say how much money was on the floor in total - but Reddit users counted upwards of $7000 just from the image.