From creepy to outright dangerous, some plants a perfect Halloween fit

Every part of the poison ivy plant is toxic, says Jacob Burns of the Chicago Botanic Garden. "Urushiol is the oil on it," Burns says. "It causes a long-lasting rash on most humans. ... You don't even have to touch the plant to get the rash, because that oil is so easy to get on your boots, your dog, the lawn mower." (Andrew A. Nelles/Chicago Tribune/Tribune News Service via Getty Images)