Stones from The Dancing Plague of 1518

Origin
The Dancing Plague (or Dance Epidemic) of 1518 was a case of dancing mania that occurred in Strasbourg, Alsace (then part of the Holy Roman Empire) in July 1518. Numerous people took to dancing for days without rest, and, over the period of about one month, some of those affected died of heart attack, stroke, or exhaustion. As the dancing plague worsened, concerned nobles sought the advice of local physicians, who ruled out astrological and supernatural causes, instead announcing that the plague was a "natural disease" caused by "hot blood." However, instead of prescribing bleeding, authorities encouraged more dancing, in part by opening two guildhalls and a grain market, and even constructing a wooden stage. The authorities did this because they believed that the dancers would recover only if they danced continuously night and day. Their agony & pain was diffused into these stones.

Effects
When placed on the ground inside or outside everyone in a 50 ft radius will dance uncontrollably until they inevitably die of a heart attack, stroke, or exhaustion. To neutralize these artifacts you must dance towards them and pick them up.