O attained consciousness and sentience in the mid-1990s, after sitting too long on a dusty back shelf of the Chicago Field Museum's gift shop. They were quick to creep out of their packaging and begin to explore the museum proper, learning how to read, among numberous other things, from the placards and displays throughout the building. The constant reading gave O a bad case of nearsightedness, as well as an impressive collection of bug and plant facts.
They initially chose their name from listening to the museum patrons talking, adopting the O sound as their own, since it was their favorite. It was only after a trip to the anatomy section that they gained a deep appreciation for eyeballs in particular, which led to him expanding the name into something suitably eyeball-sounding. They still prefer to go by O, however.
Eventually, O had managed to explore the whole museum. Unsatisfied with what was available to the public, they snuck out into the museum archives, where they discovered their first computer. Squirming into this new device was an easy feat for a Squirmle, and with the power of the computer, they entered the world of cyberspace, where they've lived ever since, becoming a purely digital entity.
While they remained a Squirmle, they did take advantage of their new digital form to add some markings they liked, as well as finally grow some of those limbs they'd seen and envied on the museum patrons. And having grown a fondness for this little bit of self-expression, they were happy to add in a scarf accessory that they change up as they please, as well as a pair of funky glasses...ironic, given that digital entities don't need to worry about eyesight.
O spends most of their time surfing the web now, occasionally popping into Discord servers and social media to share some bug facts or look at art and memes. They're in the process of building a website now, in between all the surfing, just to have somewhere to really call home. Maybe one day it'll be complete!