This is actually kind of long and weird. I have many online names, but the one I use for Newgrounds wound up being my username simply because I was very bored in my science class during a unit on the history of Earth's life last year and decided to Google search "Weird extinct animals" or something along those lines. I found a few animals that looked odd, such as Marrella, but one stuck out to me in particular: Opabinia Regalis, an ancient Cambrian animal.
In the following months, I came to love the animal, despite it being extinct. Recently, I decided I needed a new internet name unrelated to my others for my Newgrounds name, so I searched Newgrounds to see if the name "Opabinia" was taken.
My first internet name was actually chosen by my mother - it was my real full name, sans my middle name. It was for my Webkinz account. Cheers.