Nicknames

I met someone who had big bulging eyes. And if he was mad about something, they really protruded. Everyone knew him as Popeye.
There was this tall, skinny guy known as Rail...as in, "Skinny as a.........."
I asked a guy called "Pencil" why he was called that. He wasn't "skinny as a.....". He handed me a pencil and a scrap of paper. "Write this down." he said. He looked at me intently, and said, "If you keep asking questions, I'm going to kill you." I wrote it down, and later, pinned it to my refrigerator door with a magnet.