After hours of confusion/scrambling/asking friends, here's the culprit: a recent update to apparmor breaks them.

Here's a link to the bug, which also includes a workaround:
https://bugs.launchpad.net/ubuntu/+source/apparmor/+bug/2072811

Here's the very simple workaround itself:

sudo aa-disable /usr/bin/bwrap

(If you don't have aa-disable, install apparmor-utils first)

Phew. Oh my god. What the fuck,

I saw this image again today and thought to look up what the four exclusive MP3s were, only to find that they don't appear to be documented online anywhere. I wonder if anyone remembers what they are, or if they're written down somewhere... They're probably pretty funny. Also a guy named DJ Airwalk made a song called Game Boy Advance SP Tribal Edition and fucked up my ability to search for this

boosting to find the forbidden four mp3s

Here you go!
As a bonus, these also came with a printable CD cover:

I WASNT EXPECTING AN ANSWER BECAUSE I KEEP FORGETTING I KNOW VIA SOMEHOW!!!!!!!!!! OF COURSE VIA KNEW WHAT THE FOUR MP3S WERE!!!!!!!!!!!!!!!!!!!! THANK YOU VIA!!!!!!!!!!!!!!!!!