There are household pests and then...there are writing pests. Here are a few I know very well.
Scenus Repeatus: This animal is known for his excellent camouflage abilities.
Plotus Circulus: Often disguised with whimsey and wit, this creature can trick the writer into believing the plot is moving forward when in reality it's moving in a gigantic circle.
Backstory Dumpus: Although usually inhabiting the beginning of a manuscript, this rouge can also make his home anywhere the plot is lacking in forward motion.
Character Quirkus: A useful animal, although they can tend to overbreed. Control your population.
Namus Familiarus: The writer will know this pest has invaded their manuscript when they discover several characters named with similar-sounding names, or names beginning with the same letter.
Verbus Repeatus: A relation of Scenus Repeatus, this creature forces characters to give the same reactions to situations. A sign of their presence may be many characters smiling, shrugging or opening their eyes widely.
Endus Ubruptus: This trickster burrows into manuscripts of writers eager to wrap up plots using as few words as possible.
Coincidenceus Multiplus: Most often found in the last one third of manuscripts, the presence of this creature can destroy the reality of the manuscript. A close relation to Endus Ubruptus.
Scenus Nonpurposeus: A warm, purring personality; this animal is familiar to many writers who focus more on word counts and less on plot or character development.
Character Perfectus: This preening egomaniac tends to curl around the neck of a protagonist (especially in mysteries). It can be avoided by adding flaws or wrong decisions.
Elspeth Antonelli is an author and playwright. Her twelve murder mystery games and two plays are available through host-party.com. She has also contributed articles to the European writers' magazine "Elias". Her blog, "It's A Mystery," explores the writing process with a touch of humor. She is on Twitter as @elspethwrites.