cacoethes (n.)

"itch for doing something," 1560s, from Latinized form of Greek kakoethes "ill-habit, wickedness, itch for doing (something)," from kakos "bad" (from PIE root *kakka- "to defecate") + ethe- "disposition, character" (see ethos). Most famously, in Juvenal's insanabile scribendi cacoethes "incurable passion for writing."