Guys I bought a leafgreen version of pokemon. When I saw the names of ..

Did you bought the game LEGALLY or just some douchebag across the street.

Perhaps your game has a gltich, you should return it, or contact nintendo.

Your game is messed up, definitely! Did you buy this new? If so return it and get a new one from the store. If used from a store, do the same, just tell them to see for themselves it's messsed up if they don't want to cooperate, or you can always tell them you'll report them for selling bad games if it's not a "legal" version and tell them to give you your money back! (Heck, brand new they're just under $20 at Walmarts everywhere and Walmart.com.)
OK, you can't use Mystery Gift anyway, so why are you so concerned with that part?!? Or did you listen to one of these poor misinformed souls who seem to think you can and post it regularly in answers?
OK, Mystery Gift will only work if you are at a Nintendo Event!! It's used to put those tickets into your game to get to Pokemon like Mew, Deoxys, Ho-Oh, & Lugia by Nintendo officials at official Nintendo Pokemon events ONLY!!! You can spend all day trying to get it to do something, but it won't do anything but frustrate you, I promise. This goes for the other games with Mystery Gift, too, like Emerald. And Nintendo Events are hard to find and pretty rare-if you didn't catch last year's mall tour, I highly doubt you'll get a chance again anytime soon, if ever again. You can check on these at Pokemon.com, that's where they announce their events, you may just get lucky! I got my Celebi (by trading my shiny Venonat), 2Flying Pikachus, and 2 Mews between the finals in August and the Toy's R Us Mew thing September 30th, but I missed the mall tour because of my honeymoon and my boss being a jerk or I believe I could've gotten some or all the tickets and/or Celebi there. Hope this didn't bum you out too much, but that's why so many of us use cheat devices because the tickets and stuff are so hard to get.