What is this plant? What is it used for?

I am in Northern Virginia and today as I was walking came across a plant and I picked up one of its fruits. A white substance oozed out of it. What is this plant and what is it used for? Please see the photo.

Thanks for your reply. Yes it does seem to be Milkweed seed pod and yes a white substance came out as I removed it from the plant. What is the use of this plant? Is this edible? I did touch the seed pod but not the milky substance and it has been a few hours and I have not had any reaction. Here is what I found after doing a search on the subject:
"The plant is most easily identified by its distinctive pod-like fruit containing densely packed seeds. When the fruit pods mature and turn brown, they burst and release the seeds. All parts of the plant contain toxic cardiac glycosides. ... When swallowed, symptoms of milkweed toxicity usually appear within a few hours."

According to my 1973 edition of "Stalking the Wild Asparagus" , it is edible if collected at the right stages:

Gibbons wrote:The young shoots, up to six inches high, make a very passable vegetable to serve like asparagus; the newly opened leaves can be served like spinach; the unopened flower buds are eaten like broccoli, the young pods can be cooked like okra.

He goes on to explain that the plant is pretty bitter, but that the bitter taste can be removed by cooking. This is the wrong time of the year for most of those uses. I would seek newer info is serious about trying it. In general, I tend to avoid all plants with a lot of latex in the them, including dandelions.

Somewhere I read that the "down" from the tree pods was used as a replacement for kapok during world war II.

The plant is most famous as being a host for the monarch butterfly. The theory is that the young monarch larva eat the plant, making the resulting butterfly poisonous to its predators. A predator eats a butterfly and becomes seriously sick. After that it avoids monarchs. Which is one explanation for their highly distinctive markings. The viceroy butterfly tries to hitch a ride on this protection by having coloration that is very similar to the monarch's, though the viceroy isn't poisonous.

Edit: Another 1973 book of mine says that the sap can be dried in the sun or with fire and used as a chewing gum.