A series of seemingly unrelated deaths in an Amish community prompts the town's doctor to call on William Boone and Lili Marquette to help them. During the investigation, they uncover a mysterious alien probe that appears to be experimenting on the townsfolk, which is leading them to commit suicide.
- Amish: The majority of the episode takes place in an Amish community. Notably, Elijah Good subverts Boone and Lily's expectations of the Amish by revealing his Harvard education. Also, this particular community has a car that they sometime use to go far distances, and they also have electricity, although it's used in only common buildings, like the doctor's office and the freezer. Everyone uses oil lamps at home.
- Chekhov's Gun: After blasting a robotic butterfly, Boone notices that the goo inside it rapidly freezer whatever touches it. When trying to stop the probe near the end of the episode, he remembers this and starts blasting the butterfly swarm above the probe, causing the goo to drip down onto the central part of the probe, which is controlling the butterflies, and freeze it.
- Driven to Suicide: The robotic butterflies built by the probe enter the victims' bodies when they sleep and proceed to subject them to various tolerance tests, which also includes slicing up their insides with their razor-sharp wings. The victims eventually take their own lives in whatever way is convenient to them just to stop the suffering.
- It's mentioned that a new psychological condition called the Companion Reaction Syndrome (CRS) has appeared after the arrival of the Taelons, which causes people to kill themselves, as their entire worldview has been shattered. The reason Da'an agrees to send Boone and Lily to investigate is to avoid the bad PR.
- The Exile: Elijah Good is sentenced by the Amish elders to "Meidung", the shunning, for bringing the English (Boone and Lily) to them and for seeking to perform autopsies on the victims, which the Amish consider to be desecration of the dead. He isn't kicked out of the community physically, but none of the Amish are to acknowledge his existence, not even his own family (although his wife violates that rule in their bedroom, as she's proud of him sticking to his convictions). The Meidung is lifted after Boone and Lily manage to stop the probe's experiments.
- Literary Allusion Title: The episode's title references Muhammad Ali's famous quote "Float like a butterfly, sting like a bee."
- What Happened to the Mouse?: We're shown the bishop searching through the forest for his missing dog, when he runs into the probe. The scene then cuts over to the next. We never learn what happened to the bishop (or his dog), but he's not present in the rest of the episode.