"There was this established nickname tradition on the demo scene. I started out calling myself D$85 based on my initials and the year I got the C64, but I did not really like it (for one it was impossible to pronounce) and when we joined SSS I switched.

I figured I would pick an animal and I went with bagder. I quickly realized I had actually misspelled the animal, but then it also dawned on me that my nickname would be better and more special this way and so I stuck with it. Like a dyslexic badger. People have frequently been mistaking my nick for the animal ever since."

Source: https://daniel.haxx.se/about.html