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)
Patient: This one time. When I got GOATSE-d.