Laao
Laao is when someone laughs like a maniac even though there's no damn reason to. It's like they're mocking the joke, the person, and themselves all at once.
My cousin laughed for five minutes when I told him I got a D on my math test.
She cackled like a witch when I said I ate a whole pie for breakfast.
He laughed so hard he fell off the couch when I told him I failed my history exam.