One of Jupiter's moons (Titan) is larger than one of the planets (Mercury).
Ever wonder what makes a planet a planet and a moon a moon and why Pluto lost her planet card?
Well obviously a planet orbits a star, and a moon orbits a planet that orbits a star. Since Jupiter and Saturn have so many moons it is theoretically possible for one of them to lose it's orbit around its host planet die to gravitational pulls from other celestial bodies or even brother and sister moons. If that were to happen, and that moon begins to orbit the hosting star, it may be classified as a planet. Also, if that moon were to be ejected out of the solar system, and then travels alone through space, if it is found and detected it will be classified as a "rogue planet" not a "rogue moon".
Now as for our beloved Heart dwarf planet pluto. There is three criteria for a celestial body to be classified as a planet.
*It has to orbit its host star. Pluto! ✅
*it has to have a sufficient mass to have hydrostatic equilibrium, (fancy words for, "it has to be round"). Pluto✅
*it has to have cleared its neighborhood of other celetial bodies other than its orbiting satellites.
Pluto fails this one as it is among the kuiper belt and there are other object there of a comparable size. Therefore, if pluto ever starts kicking all those objects out of her neighbor hood, she may regain her planet status