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1.
noun {plan-it-nuh-vawr}
an animal, alien, planet, or star that eats an entire planet or planets.

related forms:
planetnivorous, planetnivoral
The Hubble space telescope has spotted a planetnivore star in the act of devouring a codependent planet that is orbiting around that star as reported in a science article published in the CS Monitor.
by Tsarastrophysicist May 22, 2010