Courts long ago recognized an inventor’s right to benefit from innovation, laying the foundation for modern intellectual property law. But this spawned an unintended creature: the patent troll. That’s a derisive term for an entity that acquires patents solely for the purpose of suing others for infringement, much like the folkloric monsters that extracted tolls for the right to cross a bridge. The latest mutations are called mass aggregators—secretive organizations that are basically trolls on steroids. They “operate on a scale and at a level of sophistication and complexity that would have been unimaginable a decade ago,” write Tom Ewing and Robin Feldman, two American academics, in a recent paper analyzing such entities. Here’s how mass aggregators operate.