Sort of. in pokemon XD: gale of darkness you catch a dark lugia but can be purified into normal lugia.
XD isnt at all like HG/SS/D/P/PTand so on yes it is a LEGIT game for the nintendo gamecube
Its not real you can only get it in xd gale of darkness but not in any other games
Actually it is a real pokemon. But only in the gamecube game: pokemon XD gale of darkness. I think its name is XD001 or something like that.