Curb Stomp Battle/Tabletop Games

Roleplaying Games

 * In the backstory of the game Fading Suns, the meeting between the Vau and the Second Republic (nearly at the highest point of its power and technological advancement) is the conquest of a (unknown to the humans) Vau protectorate. A few days later, a Vau ship appears, destroy every trace of human presence in a matter of minutes, and leaves a message not to fuck with this star system. Of course, humans being what they are, assemble a combat fleet to attack the planet the Vau vessel came from. The only ship to come back had been spared to serve as a warning to the Second Republic.
 * In the backstory of Planescape, it's mentioned that Sigil's mysterious ruler/protector/overlord, The Lady of Pain, has killed gods in her time...and the confrontations were not the usual, cataclysmic, ground shaking clash of the titans one would expect from a duel between major powers. They were much more of the "angry Lady = dead schmuck" variety. The only entity that has ever so much as slowed her down is Vecna, a millennia old liche and greater god, who was in the process of reshaping the multiverse at the time. Everyone else just dies.
 * She can appear in Planescape: Torment as a non-standard game over if you cause enough trouble in her city, perma-killing the Nameless One in one shot.
 * In Exalted, this is almost guaranteed to happen any time a Celestial Exalt goes in against mortals, or even Terrestrial Exalted. It's even possible to curb stomp gods if you have the right build.
 * 'The right build', of course, meaning 'being anything stronger than a regular heroic mortal'. And even then, a heroic mortal with an artifact that allows him to hit dematerialised spirits...

Card Games

 * The card Crushing Attack in Legend of the Five Rings can only be played during a battle if you have more than double the strength of the opposing army. It immediately ends the battle, preventing any actions from your opponent that might have swayed the outcome, purely by overwhelming might.