The whole plotline with the...Ghost Smashers? was it?
It's based off of the "Robo Buster" episode of the cartoon, if I'm right. That one featured a robot who also had the ability to "destroy" ghosts with Egon saying the exact same thing (the ghostly energies can't be destroyed)...the "destruction" of the ghosts had a...surprising side-effect. I think this arc will end the same way.