Haha, I respect you're at work right now, but I believe your points are explained within the articles.
Telekill is explicitly an alloy created in the modern era, and degrades over time. Even if the box was somehow affected by a temporal anomaly and sent back in time from now/near future, it should've degrade WELL before the Foundation got their hands on it. Also, crosstesting with Telekill is… generally not a good idea.
The article explains that a layer of bacteria of unkown species was discovered on the surface of the box, which is supposed to indicate that the bacteria itself acted as a preservative for the box, keeping it fresh. I also made it very clear that the Telekill Alloy was only recently manufactured. As for the cross-testing thing, I kind of agree with you there. I might change it from Telekill to a completely new and unknown "anomalous metal", as it would give the Foundation more of a reason to actually contain the thing, seeing as they already know how to contain Telekill.
Is there some reference to some mythological creature that I'm missing? Because this seems kinda… random. And not terribly interesting.
It doesn't appear to be an interesting concept because of the way I summarised it, but I've added testing logs and a horrific backstory of sorts (which kind of explains everything, including why it makes you feel worthless), which I included to make it a whole lot more interesting. Personally, I think it makes up for the seemingly random idea (I think this is a suitable point to say: You can't always judge a book by its cover :P).