Rapid Stinger is the Special Weapon used by the Roboticized Master Charmy Man in the crossover Worlds Collide. The weapon fires a rapid burst of needles at a target. Mega Man used it against Knuckles Man, but it proved ineffective.
While the weapon has not been used effectively against any of the Roboticized Masters, there is a chance, given the order of combat shown in the comic, that it is the weakness of Espio Man. Especially considering that Espio Man immediately tried to assassinate Mega Man after he got the weapon under his Chroma Camo.