A mock-heroic poem uses the formal elements which characterise the epic genre (heightened poetic diction, elaborated and lengthy similies, archaic words) to depict a trivial situation. It thus create a contrast between form and content that results in a satiric and absurd effect, ridiculing the characters in the plot and their actions.
Dryden conceived Mac Flecknoe as a satire against his contemporary playwright Thomas Shadwell. The title itself points to the absurd dimension of the poem by making Shadwell the son of (Mac) Richard Flecknoe, another writer whom Dryden despised. Flecknoe is described as a king, which recalls the status of epic heroes, but his kingdom is Nonsense, a name that mocks his supposedly heroic status. He abdicates in favor of the most obtuse of his children, Shadwell, who, just because of his intellectual weakness, is the siutable heir to the throne. The scene of the coronation, usually a noble topic, is significantly set in a dilapidated environment, thus deflating its nobility.
The mechanism of the mock-heroic genre consists in prasing the characters for their triviality and vulgarity. Thus, Dryden never directly attacks Shadwell, rather he obtains his result of belittling him by exhalting his ignorance and bad wrinting.