A gag is a piece of joke that works together with the cartoon figure to give humor. Panel cartoons and comic strip use gags a lot, even though the latter do not need to be very funny in order to work.
The gags normally used can be classified into the following:
The joke is when something or someone is out of place. For example having lower class people talking about high-class subjects.
Extreme understatement gag
Like talking to a millionaire about how decent his car is.
Superior position gag
There is a hidden element in the picture, where the viewer sees, but not the cartoon character.
Character comedy gag
The viewer has prior knowledge of the character and knows how he will respond to some situations. When that situation is shown in the cartoon, the character responds as expected.
Generic cartoon gag
The cartoon is placed in a familiar scene like on a deserted island, with cannibals.
Gags are very important in cartooning. There is a saying that 75 percent is idea and 25 percent is drawing.