I actually browsed the general site for once, and noticed that there wasn't any references to Pico on the Newgrounds page. Does anyone familiar with making entries and Newgrounds as well think a mention is deserved?
For reference, Pico is the main character of some of the games of Tom Fulp, the creator of Newgrounds. Most of the games are over a decade old, and of amateurish quality, but gained popularity within the site itself over time. This was likely due to the position of the character's creator, the absurd and violent content of the games, and the close-knit community that pioneered the earlier days of amateur flash animation and games. Eventually, "Pico Day" would become an official "holiday" of sorts on the site itself, wherein art, animations, and games featuring Pico and his friends would be the theme of the day.
So yeah, it's an older meme that's pretty much limited to a single site, but has an arguably important role in it.