submit a writing proposal (what you would like to write about and how you intend to prove your viewpoint of your definition) and a tentative outline of how you think you will organize your paper
For your proposal, think-
If you are wanting to argue that the definition of a fictitious monster should be expanded (like what Alexander did with mermaids)
what monster are you going to choose
how should it be expanded (think: how is the monster used now? What does it represent?
what sources are you going to use to prove your definition.