What is the difference between epic and mock epic?
This is a great question. It is best to start with a definition of epic and then move to the genre of a mock epic.
An epic is a long work in poetry that tells the story of a hero and his struggles; there is usually a journey and great battles. It is also usually written in dactylic hexameter. The most famous epics are Homer's Iliad and Odyssey, and Virgil's Aeneid. In the Iliad we read of the great hero, Achilles and the battle between the Greeks and Trojans. In the Odyssey, we read of Odysseus and his long journey back home and his battle with the suitors. In the Aeneid, we read of Aeneas and his call to find a new country for his people.
A mock epic is something that has the feel of an epic, but the content is pointedly not heroic. The perfect example is the poet Ovid. The Metamorphoses is written in dactylic hexameter, but the content is not about a hero. Often times it is about the amorous adventures of the gods as they seek to seduce human women.
To answer this question, let us start by defining the characteristics of an epic. Generally speaking, epics are long poems which detail the heroic exploits of one or more characters. The epic highlights the character's bravery and courage and, often, the many struggles that this character is forced to overcome. One of the most famous examples of an epic is The Iliad, a story set during the Trojan Wars.
As you can probably guess from the title, a mock epic does exactly what it suggests: it works by 'mocking' the traditional epic. In other words, it contains all of the characteristics that you would expect to find in an epic, but it is far less serious since it focuses on a silly or trivial matter.
A famous example of a mock epic is "The Rape of the Lock." This poem has all the grandeur of an epic but instead of focusing on a heroic quest, the action focuses on a baron who steals a lock of hair from a lady, a far more trivial activity.