I also give my friends the most random nicknames.
Like, one of my friend's knocked over a whole bunch of stands in the Band Hall and one of the assisstant band directors said "Bulldozer Helen" and I came up with "Avalanche Helen."
Another time, another friend was at tennis practice with me and the coach said "Good job, Pigtails." So, I told her I was gonna call her pigtails.
Another friend's name is Robyn Hood, simply because her name is Robyn.