Guild Wars 2

Suddenly, nobody offers it and its price has risen since some days ago

http://www.gw2spidy.com/item/39467

With such a low volume, someone probably thought they could buy out the stock and relist at a higher price point.

It may work in the short term, but they are probably going to be stuck with overpriced inventory as more of the item is dropped undercuts the current TP price.

There are also two other items that is the same thing with a different name.
Rotbeard’s Treasure
Tortured Root

Then there is Book of Rabid Deeds which you can buy from Dwayna’s temple. So if someone bought this out to make a profit they are relying on both low drop rate for this item and ignorance of other sources of the equivalent item.