Poisoned Tooth

+Jeremy Kostiew asks
"I found a, uh, tusk. That's the best way I can describe it. It's made from some kind of enamel, or ivory (I think!), but there's no root like a tooth might have. It's sharp on both ends, but the curve of each point looks like it came from different animal. Longhorn and buffalo, maybe? Not a clue. It's smooth enough that it's hard to hold, and I can't get any of the dogs to go near it.

The strangest bit? It was wrapped in the roots of an old, dead stump I unearthed during landscaping. A month later, grass still won't grow in that spot. Can you help me out?"

Jeremy, you've got a Poison Tooth on your hands. It doesn't create an actual poison, despite the name, but anything pierced by it will be infected with a magical decay. They were often used against large animals.