This burger was purchased in 1995 by two teenagers in Adelaide, Australia.
Neetz and Dean, now grown-ass men, say on their Facebook that: "As far as we know, it's the world's oldest."
Like any proud owners of two-decade-old food, Neetz and Dean keep their burger in a little wooden box with a padlock.
Hey guys, don't eat that. No. Don't. STOP IT NOW.
Oh, and they have a (weirdly catchy) song called "Free the Burger" which tells the whole story:
BuzzFeed has previously looked at the mould growth on burgers after 30 days, comparing seven different restaurants, with McDonald's showing no mould at all.