A humorous imitation of a serious piece of literature is called -

Parody - 
writing, music, art, speech, etc. that intentionally copies the style of someone famous or copies a particular situation, making the features or qualities of the original more noticeable in a way that is humorous:

Comedy - 
a (type of) film, play, or book that is intentionally funny either in its characters or its action:

Satire - 
a way of criticizing people or ideas in a humorous way, especially in order to make a political point, or a piece of writing that uses this style

Limerick -
a humorous poem with five lines

Source: Cambridge Dictionary