When one person, preferably one who isn't that funny, makes a joke that isn't funny. In the silence following the joke, one person may release a loud sarcastic singular "HA" to show this unfunny person to return to their position of not being funny.
Unfunny friend: Hey guys "insert stupid joke"
everyone else: *silence*
other normal friend: "HA"
everyone else: *laughs at the devastation of unfunny friend*
other friend: dude that devastation laugh was awesome.