Origin
While shopping one day on a busy street corner in Tokyo (don't ask how he got there), James happened to come upon an extremely rare Magikarp that just... happened to be for sale. In fact, the shop owner PAID him to take it, and James was more than happy to oblige. Unfortunately, it ate all the money he had with him and almost took off one of his fingers by the time he got it back to Jessie and Meowth. After mauling James for his idiocy, Jessie and Meowth attempted to throw it out the window and forget all about it. Of course, the Magikarp had other ideas...
So began it's reign of terror, as it flopped around the world causing all kinds of destruction and general chaos. 'Cause when there's a Magikarp flopping around, eating people, there's gonna be chaos. And for the next year, that's pretty much all it did...

Sightings:
The following is a list of just some of the places it was spotted during that time:
*Flopping around schoolyards, terrifying children and eating their homework. (Hey kids, go try it: "The Magikarp ate my homework!" Yeah, right. :P)
*Swallowing passengers by the boatload somewhere off the coast of Florida. (I understand that the ones on cruise ships have the most interesting flavor.)
*Masquerading as a yummy-looking fish on a local seafood buffet. (Hot tip: Don't take the fish that's eyeballs are still moving.)
*Picketing at a "Worm Abuse" protest. Just because it prefers you to bait your line with something a little larger. :P
*In the employ of a gang of pirahna bent on world domination. (I wouldn't go wading in any rivers if I were you.)
*Singing karaoke in a bar somewhere in Japan. It's not just bloodthirsty and vicious; nope, it's multi-talented.
*Coming soon to a restaurant near you. And no, you won't be eating it... well, you get the picture.
*Hiding in Jessie's sock drawer, just waiting for it's next unsuspecting victim.
*Vacationing somewhere off the coast of a deserted island. Hey, even a bloodthirsty freak of nature needs a break sometime.

Where is it now?
Where is it now? Well, Karpy has retired to a kiddy pool on the Team Rocket HQ's back lawn, where it still eats the occasional... "unfortunate" trainee that just... "happens" to be in the wrong place at the wrong time... But it occasionally serves as the protector for this very website. Yes... you should be scared...