An example which isn't on the trope's page:Once upon a time, there was a superhero universe which was slightly different from the others. For starters, there were relatively few superhumans: they were at the beginning of the discovery and public exposure phase. And every one they did have, regardless of the moral side they were on, shared a common origin.
They were all dead.
Or rather, they had been dead. Each one had died in an uniquely excruciating way -- and come back. They were alive again, yes. They had powers. They healed at paranormal rates and would never age from the biological point of their demise (which wasn't always a plus). But in order to get all of that, they'd died. Every last one.
So in this world, you had a megachurch. One with its own vision for the world. And the leader of that church had a visitation, one that told him the final war was coming and the church was going to need an army. Volunteers were called for, men and women to step forward for a chance to serve their deity more directly than they'd ever dreamed.
And one by one, those volunteers were killed, each in an uniquely excruciating way. New methods of murder were invented just to make sure there would be no repeats. Removal of fluids a cubic centimeter at a time, that was pretty creative. Hundreds of people, none of whom had been told what they were volunteering for, systemically exterminated -- just so the church could watch the bodies and see if any of them moved.
http://tvtropes.org/pmwiki/pmwiki.php/Main/SuperpowerRussianRoulette
They got six back...
Bill Willingham's Elementals. Some images stay with you.
There are many universes like this, ones where the only way to gain power is to court death. Most of the mutations are lethal. The virus has a 90% fatality rate and you don't want to see the majority of the survivors. You will no longer care about human emotions, but at least you didn't go full autistic. You'll either be dead in two days or you acquired superhuman intelligence and you'll be dead in two days.
And in every last one of their universes, give enough time and understanding of the process -- someone will call for volunteers.