gaffewww
A joke that starts with something hilarious and finishes with something so gross it makes you want to vomit.
'I told my dog a joke about a chicken and a cow. He laughed... then ate my homework.'
'My friend said a joke about a pizza. It ended with a whole bunch of spaghetti coming out of his nose.'
'I told a joke about a ghost. It ended with the ghost throwing up on my shoes.'