Brew:Rules/Guns and Out-of-scale Opponents
From Drinking and Dragons
One of the important aspects of the campaign is that there are people, creatures, and whatnot that are operating at a level higher than that of the cast. For as powerful as the cast are, they are still vulnerable human college students.
The following rule addresses conflicts that involve guns or entities too powerful for the cast. When such an opponent attacks, the target cast member(s) must make an Overcome roll against a difficulty set to the attacker's result, getting at least a tie, or be taken out.
Since this is an Overcome roll, cast members may decide to succeed at a cost.
Given how potent this is, it won't come up in play very often.