It was a pokemon you could catch (Was it on Cinnabar?) by surfing up and down the coast after doing some tasks to trigger a glitch. The same glitch was more popularly used to replicate items, such as rare candies or masterballs :3 I think it was whatever item was in a certain slot in your bag would hit the max of how many you could hold. 
But, catching it would make your Elite Four records glitched permanently and irreversibly for the duration of the game. 
http://www.youtube.com/watch?v=-tOyBahKkbk...THey do it differently than I used to. I don't remember how I triggered it but I don't remember ever talking to that guy and I remember going into the Safari Zone to trigger a glitch other than the glitchy town which was fun, too 
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