gasser \GAS-er\, noun:
1. Something that is extraordinarily pleasing or successful, especially a very funny joke.
2. A person or thing that gasses.

“You’re gonna whiff like Reggie Jackson today, pal,” I said. By the third hole, Blind Bob led by seventeen shots. It was a laugher, a gasser. If it were a fight, Big Al would’ve been counted out, taken to the hospital, and killed by Clint Eastwood by now.
— Rick Reilly, Shanks for Nothing

This was very funny indeed, the gasser of all time. When Max announced the name at the briss those thirty-seven years ago, perhaps all the guests, including Dave Raskin, had split a gut or two laughing.
— Ed McBain, The Heckler

via Dictionary.com.