From Wikipedia:
Harris’ best known creation, Orville the duck, came about after he saw some green fur lying around backstage at a performance of The Black and White Minstrel Show in Bristol.
Orville […] was “a huge, gormless, falsetto-voiced green duckling sporting a nappy fastened by a giant safety pin”.
Harris recorded “Orville’s song”, written by Bobby Crush. It made the Top Ten in the UK singles chart in 1982 and sold 400,000 copies.
It was later voted the worst song ever recorded.