Aside from the Mystery egg, what was your first 2nd gen Pokémon you caught? Mine was a Ledyba. It's not that hard to find, but I think it's cute.
Spinarak was the first of the new set that I captured. Coincidentally, it was also the first one I found. I did not plan this (I just tend to catch things I like the looks of in some way), but it is a humourous little happenstance.
I would assume Odd Egg counts. It was released along with the rest of the update, so the only one to decide whether or not that's okay would be you.
Swinub, and boy was I excited. <3 Then I proceeded to find Spinarak and Wooper and go crazy browsing lol.
Beverly Crusher my Chikorita, if we're not counting the TARDIS. Seems to be a popular first choice, but, who can say no to that face?