Even If the answer is not a devil fruit... I need to know why.

He didn't have the thing before Banchina died, so I don't think it's related to his father or his mother.

Maybe it's just a piece of clothing.

Then... and I may be stretching the theory a bit, here it says that the striped thing on his chin is the rest of the mushroom. And it kind looks like Usopp's striped armband. I know he sometimes take it off, or it up, so it's not part of his arm. But what if he just kept that part?

And then we have this moment, when Nami had a fever.

We know Luffy ate the fruit, and we know Sanji is genetically modified, so what's Usopp deal then? It doesn't feel like a lie or an exaggeration, he is saying it at the exact same moment Sanji is.

Then we got Usopp at the Baratie refusing to eat the mushroom because he ate a "poisonous" one when he was a kid. May be it wasn't poisonous, may be it just tasted really bad.

Do you remember Jango? The second in command to Kuro's crew, the guy who walked backwards and hipnotices people (and himself). He got that power by eating a mushroom that grew on his chin, and it tasted awful.

Usopp does swim on Cocoyashi island and in Punk Hazard while holding Robin, but my question is...do they sink if they don't know they had eaten a devil fruit? I have a theory... that's: Usopp ate a fruit but it's a simple/primordial/unevolved one, as a kid, but doesn't know it was a devil fruit.

I was starving and you fed me ♥