In the Deep Space Nine episode The Muse, a mysterious woman named Onaya arrived at the station and offered to help Jake Sisko with his book.
He was dealing with some serious writers-block before she arrived, but afterwards became overwhelmed with new ideas and quickly worked himself into exhaustion. After Jake got a nosebleed and collapsed at the Replimat, he was taken to the infirmary, where Bashir found that his brain was on the verge of total synaptic collapse.
The crew soon learned that Onaya was actually a being of pure energy that feeds on the brainwaves of creative people. By activating their full creative potential, she was able to extract their energy and use it to prolong her own life, killing her victims in the process. She defended herself by saying that, although her victims would die, they would be immortalised through the art they created with her intervention.
Jake Sisko was able to survive the ordeal when Onaya was exposed and fled into space, but her other victims from the past include a ton of famous creatives from history, including the Earth poets Catullus and John Keats (as well as the Cardassion architect Tavor Kell). There's no telling how much of humanity's greatest works of art were actually the result of this deceptive alien parasite.