Aye. There's an ongoing legend that one of the Allied men in the trenches in World War II left some Chistmas Pudding behind in a retreat. The German soldiers thought it was some kind of explosive and blew it up.
I've also seen (and tasted, more's the pity) one that was sour. Yech.
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Re: A bad one
I've also seen (and tasted, more's the pity) one that was sour. Yech.