The immovable object and the unstoppable force are both implicitly assumed to be indestructible, or else the question would have a trivial resolution.
The paradox arises because it rests on two incompatible premises—that there can exist simultaneously such things as unstoppable forces and immovable objects.
This term originates from a story (see Kanbun § Example) in the 3rd century BC philosophical book Han Feizi.
Another ancient and mythological example illustrating this theme can be found in the story of the Teumessian fox, which can never be caught, and the hound Laelaps, which never misses what it hunts.
Realizing the paradox, Zeus, Lord of the Sky, turns both creatures into static constellations.