Deadly Nightshade

The name really ought to have tipped you off. Its official name is Atropa belladonna, and its purple flowers and shiny black berries are actually very pretty. Just don't eat them. The plant, whose berries are actually quite sweet (don't ask how we know), can cause delirium, hallucinations and eventually, death...but don't go hating Atropa belladonna quite yet. This plant is also the source of the drug atropine, which is commonly used on heart attack patients and less commonly used on victims of nerve gas. The nightshade family itself is quite diverse: Deadly nightshade's distant cousins include potatoes, tomatoes, eggplant and peppers...oh, and tobacco.