Back in the 50's (Last time the wings won the cup, before the last two) this doood that owned a place which sold squid went to a game and throw and one of the buggers on the ice. During this time their were only two rounds of playoffs, each best of seven. So it took 8 wins to win the stanley cup.
8 wins
8 arms, legs, tentacles...whatever
--it's a symbolic thing.
AS to why forty years later the Michiganders started up the act again i do not know, except that it is pretty cool.
Also, those octopi usually aren't toys. And they have slowed down quite a bit because it was interferring with the game play.
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When life gives you a lemon, wing it right back and add some lemos of your own. -Calvin(Bill Watterson)