The one on the right looks pretty normal and the one in the middle has a weird spot forming, but that one on the left... oof. The guy ended up sending it to a lab to have it analyzed and the thing has been ravaged and devoured by fungi. If you read the article linked below, the lab determined that there must have been a fungus inside the packaging before it was sealed.
This is really upsetting to me -- not because I personally love Twinkies or have any old ones out in my garage, but through movies like Zombieland and lots of other fiction, I was led to believe that in a post-apocalyptic world, Twinkies would last forever. Seeing that one on the left makes me think I might not even want to survive a nuclear war. If I somehow make it through World War III and survive for years by eating garbage and my neighbors only to finally discover a Hostess truck full of Twinkies and then learn that they are all gross and shriveled up, well, I'm starting World War IV. That's some Twilight Zone level bullshit, right there.
Link: A Disturbing Twinkie That Has So Far Defied Science (NPR)
