A disgusting picture of a man stretching his anus extremely wide. One of the oldest jokes on the internet is to link the picture to internet forums and chatrooms, renamed to look like something else like "happybunnies.jpg" . Often causes people to freak out.

1) To cause someone to inadvertantly navigate to the website of the same name

Website featuring a picture of a man practising anal stretching. Usually, it's a link given to unsuspecting people so when they check it out, they get hit by the image and are supposed to be scarred for life by it. This man is not a hermaphrodite.

Although it originated from a picture of a man streaching his anus amazingly wide, GOATSE is now a verb.

GOATSE: verb.
To cause someone to navigate to a website, which usually contains only one image; by giving a faulty web adress. Said image must be disgusting and scaring. The beauty of GOATSE is that a person only realizes what it is once they have seen it. HAHAHA! PWNED!

(Note: The original GOATSE picture is sometimes referred to as THE GOATSE)
(Note 2: The goatse is one of a huge amount of suh websites)

An internet photo of a man streching his anus to un-realistic proportions.

Named for the address of the original website, (goatse.cx) which has since been taken down but not before achieving Internet noteriety. See also tubgirl.

The website featured a man bending over with two hands stretching apart the largest bodily orifice in the world. You could see inside several inches deep.

Since then, parody websites have sprung up showing everything from stretched-apart doorways to red-filling-ed cookies.

A site that is commonly linked to by Internet trolls in order to shock unsuspecting users with the image.

And now, the origins of this madness:
The alt attribute on the image, "stinger", actually comes from the EFNet #quake channel. The image itself was discovered on a webpage. Goatse.cx was created by a #quake member expressly for the purpose of displaying the image.
The image hello.jpg originates from a set of 40 images depicting the man performing various anal sexual acts.