[the phantom]

In elementary school I used to do all sorts of things to entertain my friends. I would steal chalk from the chalk board and books from the inside of my teacher's desk, and I'd always do it while the teacher was in the room watching us. I was slick. One time I went up to talk to the teacher at her desk and stole a book, a pencil holder, and her glasses off the desk while she was looking right at me and talking to me. I would always place these items on the teacher's desk the following day when she wasn't in the room, and I'd always have a sticky note attached that read "from the Phantom". Eventually a classmate blew the whistle on me and I got in trouble.
Later on, when I was in high school, the kids in my music theory and music composition courses started calling me 'phantom' because I was always singing or humming Phantom of the Opera tunes. (I love Phantom of the Opera) This nickname caught on with my friends because I was still known for doing all sorts of sneaky pranks and never getting caught.
I really liked the sound of "The Phantom", it sounds so mysterious, so I let everybody call me that and have used that name for e-mail and stuff ever since.