The unworthy can suffer such fates as simply being unable to assemble the item in question (the Millennium Puzzle) to outright death (the Millennium Ring and Eye)
Then, you could cast them for the mana cost straight from the sideboard
I'm sure there's loads of discussion to be had in the Cardsphere Discord about the pluses and minuses of various models, so pop in if you want more information
Collection Tins: The card displayed in the window of the metal tin
Say it with me now

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