The Fallout Show Canonises An Urban Legend About Vault Boy's Thumbs-Up

thegamer.com:

Stop me if you've heard this one before: Vault Boy isn't actually giving us a thumbs-up. Instead, the jolly little guy is actually comparing the size of a distant mushroom cloud to his thumb, to see if he's safe from the blast. This has been passed around as fact in the Fallout fanbase for years, but in actual fact, it just isn't true - the original creators of the series really just intended this to be a thumbs-up, nothing more.

However, after years of the urban legend spreading across the community, the Fallout series has just gone ahead and made it canon. In Prime Video's Fallout show, one of the main characters repeats this theory as fact, establishing that Vault Boy's iconic pose isn't as reassuring as it initially appears to be.

Slight spoilers for the opening few minutes of Fallout ahead.

In the first scene of Fallout's first episode, we get a snapshot of what life was like just before the bombs fell. And I mean, just before the bombs fell, because the scene ends with the start of the Great War in 2077.

But right before the world ends, one of the lead characters tells his daughter the story behind Vault Boy's iconic thumbs-up. Here, he says that in the event of a nuclear blast, you're meant to stick your thumb out to see if it covers a mushroom cloud. If it does, start running. If it doesn't, there's probably not much use in running.

This is the exact story fans have been sharing for years now, and it's easy to see why so many found it believable. Not only does it fit into the world of Fallout very nicely - with even the cute mascot having a morbid backstory - but Vault Boy also has one of his eyes closed. This makes it look like he's seeing if he's within a "safe" radius of the bombs, not just posing for the Vault-Tec propaganda material.

Putting this in the show is a departure from the thumbs-up's original meaning - which had no meaning behind it whatsoever. As reported by Screen Rant, the former Fallout producer Brian Fargo has previously said