Long story:
Back in '91, (Yes, I'm old, get over it.) I started playing a game of GURPS Supers with a bunch of army guys I knew. My character was Prowll, a smart (150 iq, not 'reed richards' smart) speedy guy that had the unfortunate past of being a half-man, half tiger genetic experiment. So the only place he could really fit in was furry conventions. Anyway, he was also really good at organizational skills, management, and legal wrangling, so he ended up being the 'head' of the JLA-type group that got created.
In this group was another fellow with the same first name as myself. As it's not a common name, we both hadn't had this issue before, and so both of us responded to every time our name was mentioned. As a result, people started calling him 'Red' for his flaming red hair, and me, Prowll.
The nickname stuck. People would introduce me to THEIR friends as 'Prowll'. I knew one guy for 2 years before he realized I wasn't named by hippies or something. It was on my business cards at work.