Upon purchase I called mine "Xochimilco" after the lake, obviously. It isn't AS unoriginal as it sounds, because I actually did stay in Xochimilco city for two weeks on a mission trip. Although, I spent almost the entire time laying on a mat with uncontrollable diarrhea. (Their tap water needs a lot more than a declorinator.)
However, that name lasted for all of two days before my friends started calling it "your green dragon".
"Ohmigosh, your green dragon is so creepy/cool/cute!" Everyone was calling it that, and it didn't bother me because of The Green Dragon pub from Bree in Lord of the Rings. Although, I don't think any of my friends who we're calling it my green dragon made the connection, or even read the books.
So, since I like LOTR more than Montezuma's Revenge, I officially changed his name. I don't think he noticed.