In Revelation Wormwood was the name of the star that fell from the sky when the third angel blew its trumpet, poisoning one third of the waters of the world. Many people have taken the fact that Chernobyl means Wormwood in russian, and have taken the nuclear disaster there as a sign of the end of the world. This is in fact a myth, and Wormwood is translated as polyn (thanks to housecat for pointing this out)