Datura stramonium/jimson weed

It looks like some kind of Datura

Datura stramonium is poisonous to people, and Merck's Veterinary Manual says it's dangerous to "All" animals:

It is listed here in the last section ("Dangerous season: All seasons"):
http://www.merckmanuals.com/vet/toxicology/plants_poisonous_to_animals/range_plants_of_temperate_north_america.html

Datura stramonium is widespread in much of the the U.S., and there are also some native Daturas.

Angel's Trumpet (Brugmansia Daltura) Did it bloom? Mine has large white trumpet flowers. Here in CT, the seeds survive the winter and the plant does not. It can get to 4' or so with many flowers.

I do not see it as a weed however, the sap is hallucinogen/poison.

emerogork2: just FYI, brugmansia is a completely different plant than datura. brugmansia is commonly known as an angel's trumpet (the flowers hang down) and datura is commonly known as devil's trumpet (the flowers point up)

Sweet_betsy identified it correctly straight away - it's Datura stramonium aka Jimson Weed or Thorn Apple.