This is NOT a file format that corrupts itself. This is a file reader that corrupts files. There's a big difference. Nothing about the format itself causes or requires corruption. A better tagline would be "decayfmt is a social contract enforced by pinky promise".

Reminds me of Tie::Hash::Cannabinol:

  Tie::Hash::Cannabinol is a completely useless demonstration of how to use Tie::StdHash to 
  pervert the behaviour of Perl hashes. Once a hash has been tied to Tie::Hash::Cannabinol, 
  there is a 25% chance that it will forget anything that you tell it immediately and a 
  further 25% chance that it won't be able to retrieve any information you ask it for. Any 
  information that it does return will be pulled at random from its keys.
  
  Oh, and the return value from exists isn't to be trusted either :)

[1] https://metacpan.org/pod/Tie::Hash::Cannabinol

A virus I wrote in the '90s did just that - every time you opened a file, it damaged a small random part of it. My plan was also to randomly change the digits of numbers when printed on paper. I wrote this because a friend of mine managed to steal my source code during my naive XOR encryption. The "encrypted" files had a bunch of zeroes, and he saw my password. My virus worked. First, it damaged his working copy; then he tried to copy the backup, but in doing so, he damaged it, too, even though he claimed his backup diskette was write-protected. The virus didn't spread because I knew how evil it could be - just as evil as MS-DOS, which would run a hidden .COM file without thinking twice. So many fast typists like me were often mistyping "DIR" as "DUR", so I just put my virus in a hidden DUR.COM, copied it into the empty allocated space of COMMAND.COM (less than 200 bytes), and printed out "Bad command or file name". So, the theft was avenged!

P.S. I didn't specify, I didn't have my own computer, only used computers at school and my friend's personal computers, leaving "encrypted" files in case I forgot to bring my diskette. So, after he stole my code and some personal files, her never left me alone on his computer, but he never thought I would infect his computer so easily right in front of his eyes without him realizing it!

From what I remember, MS Paint do something similar when you would save the image as a jpeg. It would apply the algorithm each save and the image would degrade a bit each time. It was super fun.

> This is a social contract

What's the other side of the contract? Why would a reader oblige to corrupt?

Kind of like how human memory works, if I understand correctly.

Seems like there is no mechanism to allow non-corrupting reads from authorized processes? Begs the question then of what the point of this is. Pure novelty, or truly something that could be used in practice?

I initially thought this would be part of a fuzzer.

You might look into (Norbert) Weiner functions.

Should have patented it and licensed it to Snap

This sounds like Excel when you open a CSV file.

I thought something like this should be part of the file system to make it even more laborious to by pass

Would you please stop inventing more ways to enshittify the world?