"The last resort in a deck of cards is...J0KER"
J0KER is a manga character created by writer Yuu Maki and illustrator Katsumi Michihara. A one-shot OAV (Original Animation Video) titled, "J0KER - Marginal City", was also produced based on the manga.
According to the storyline, J0KER is a genetically engineered shapeshifter (gosei ningen or "combined human") who can take on any humanoid form. J0KER was created as part of a Special Police Task Force and is licensed to kill. He/she was engineered with enhanced physical strength and reflexes...and silver eyes.
I use J0KER as my IRC nick, until recently when I had to switch to DaJ0KER. I chose this nick because it is unique and not too many people have heard of this character. The most common reaction to this nick is, "Where is Batman?" ^_^ Notice it is J0KER and not Joker, the '0' is the number zero and not a letter.