At the bike shop I work at my nickname is Lizard. Born from the fact everyone used to call me the wizard (because I like 70s murals, fantasy novels and am a deft hand on the line borer), until we had a guy visit who used to pretend he knew everyone really well despite being a total dweeb. 

Anyway on one occasion he came in and proceeded to talk to me for 45 minutes or so while I worked on his bike all the while calling me the lizard. Everyone else thought this was hilarious and it’s stuck ever since.