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Rigsy was a graffiti artist who was forced to paint over his own work as part of his community service. The Boneless originally took the form of graffiti art before learning how to take on three-dimensional form. (TV: Flatline)
The Pararachnids graffitied the Moon during their invasion of Earth. According to the Sixth Doctor the graffiti read, "All Hominid Aboriginals of This Place are Known for Attempting to Mate with Their Own Persons and All Pararachnids are very Much Better than Same." (PROSE: Moon Graffiti)