TED-Ed Lesson: In the middle of Florida’s Apalachicola National Forest, a bizarre, almost magical scene is unraveling. Sliding a metal strip over a wooden stake, a master summoner is sending deep croaking noises reverberating throughout the area. And, as if in a trance, hundreds of earthworms begin emerging from the soil. What’s going on? Kenny Coogan explores the tradition known as worm grunting.