Everytime when you lose in event like Gunslinger/Duelist Trial, Card you get is normal monster card that will random everytime you lose.In each season there is different loser’s card and there is 1 card in loser pack that’s Extremely Rare usually at 4-5 at Japanese Card Rate I call it Secret Normal.
First Season Spring 2007 It’s Thunder Kid
Other cards in Loser’s Pack can see it at http://www.geocities.jp/yugiohonlinepart000007/make01.html
Second Season Summer 2007 It’s Haniwa
Other cards in Loser’s Pack http://www.geocities.jp/yugiohonlinepart000007/make02.html
Third Season Winter 2007 (This Season) It’s White Dolphin
Other cards in Loser’s Pack in This Season http://www.geocities.jp/yugiohonlinepart000007/make03.html
It’s seem like Konami will make 1 Secret Normal in each season and it’s very rare card hard to get it even you lose a lot but if you aren’t collector this cards mean nothing to you.
I update Link now there is more useful link seperate by Category more Online Card List also (JPN language).