Lavender Unicorn Syndrome occurs when, instead of using a characters name or a pronoun, you repeatedly use other descriptors for them, such as "the baker," "the ninja," "the dragon."
Common in Fan Fictions, the term spawned from the Friendship is Magic /fic/ board where writers would refer to Twilight Sparkle as "lavender unicorn" rather than using her name to describe when she was doing something.
"As Twilight Sparkle walked into the room, the lavender unicorn lifted the book from her shelf with a wave of her horn."
That's Lavender Unicorn syndrome right there. We have pronouns for a reason, people.