The opposite of an ordinary planet that is gravitationally repelling, while still being similar to an ordinary planet, could be referred to as an "extraordinary antimatter planet." Let's call it "Anterria." Anterria would still possess similar characteristics to an ordinary planet, such as being spherical in shape, orbiting a star, and potentially having an atmosphere and a solid surface. However, it would differentiate itself through its unique antimatter properties. Antimatter is the opposite counterpart of ordinary matter, with the same mass but opposite electrical charge. Therefore, Anterria would be composed predominantly of antimatter particles instead of ordinary matter particles. As a result, the fundamental forces that govern Anterria would behave in the opposite way compared to an ordinary planet. Ordinarily, planets are subject to the force of gravity, keeping them bound to their star and causing them to attract other objects towards their surface. However, on Anterria, the gravitational force would be repelling rather than attracting. This means that objects, including other celestial bodies, would be pushed away from Anterria rather than pulled towards it due to its anti-gravitational nature. In this unique scenario, Anterria and an ordinary planet would exhibit opposite gravitational behavior, but they would still share many similarities in terms of their planetary characteristics and overall structure.