I might as well take a shot at explaining. Pascal's wager says I might as well take on the relatively small inconvenience of going through the motions of believing in God, because if the small probability event occurs that he does exist, the reward is extremely large or infinite (eternal life in heaven presumably)

Pascal's mugging instead makes this a relatively small payment ($5 as Yudkowsky phrased it) to avoid or mitigate a minuscule chance that someone may cause a huge amount of harm (putting dust specks in 3^^^^3 people's eyes or whatever the current version is)

Thus for both of them people are faced with making some small investment to, should an event of minuscule probability occur, vastly increase their utility. A lottery ticket