|Spoiler Alert: This page contains spoilers. Read at your own risk.|
Poisoned Bees (毒蜂) is a Sensory Systematic Type Magic that Kuroba Mitsugu designed and named. It increases the targets pain perception infinitely until death. However, if the target were someone who has a high pain threshold and was able to employ Counter Magic before the shock led to death then the spell would unravel. Also, there is no effect on opponents who can cut off their pain sensors. In terms of killing power, Poisoned Bees is well below Grim Reaper created by his uncle, Yotsuba Genzou.
Still, "Poisoned Bees" is not exactly magically inferior to 'Grim Reaper'. The greatest advantage to Poisoned Bees is its ability to finish an opponent with the tiny prick of a pin. On the other hand, Grim Reaper requires personal delivery, leaving behind wounds on the corpse and blood everywhere. In comparison, Poisoned Bees only leaves behind a nondescript wound that would be hard to link as the cause of death. When faced with a victim of Poisoned Bees, poison then asphyxiation would be assumed, but the corpse would leave behind no evidence for either hypothesis. For assassination purposes, Poisoned Bees is a superb magic.
Another asset to Poisoned Bees is that this magic can be used by other Magicians. Unlike most sensory interference magic, Poisoned Bees has an Activation Sequence that is not streamlined to be caster specific. Naturally, this requires a degree of acclimation, but now all Kuroba agents employ Poisoned Bees as their trump card.