This event was distributed to players at the New York Pokemon Center: Gotta catch 'em all! Station,
and the collection for various PCNY Pokemon ran across the period of November 22, 2001 to March 13, 2003.
The schedule of Pokemon changes weekly, and players was restricted to collecting one Pokemon per week per visit.
This Pokemon was distributed as an egg, and has a 12.5% chance of being shiny.
The egg was already hatched by the contributor.
The dates for distribution was:
December 28, 2001 to January 31, 2002
January 17 to 23, 2003
A more comprehensive schedule list can be seen here.
DUE TO HAVING AN EVENT MOVE,
THIS POKEMON WILL NOT BE LEGAL WITH ANY VIRTUAL CONSOLE RELEASE
(AND BY EXTENSION, CANNOT BE TRANSFERRED TO GEN 7 AND ONWARDS).
Original Thread and Credits to Gold Ursaring!: