Mood slime
From Transformers Wiki
Mood slime (also known as psychomagnotheric slime or psycho-reactive slime) is a peculiar form of ectoplasm with unusual empathic properties. That is to say, it reacts to human emotions, both positive and negative. Mood slime can have different properties depending on what emotions it's reacting to. Negatively-charged slime can create dimensional rifts that ghosts can use to cross over or empower themselves. Positively-charged slime can be used to weaken ghosts and effectively exorcise a ghost out of anyone they are possessing.
Fiction
Transformers/Ghostbusters
Prior to their encounter with the Transformers, the Ghostbusters used gallons of mood slime to get the Statue of Liberty moving. Ghosts of Cybertron Part 5
In 1994, the Ghostbusters left a canister of mood slime inside Ectotron's vehicle mode, along with an occupied trap, empty traps, and enough crumbs to compose another meal. Winston Zeddemore proposed using the slime to defeat Kremzeek only for the Ghostbusters to instead let loose an electricity-feeding ghost, physical contact between both electrically composed entities dissipating them. Ghosts of Cybertron Part 4
The mood slime soon proved useful when Ectotron was possessed by the ghost of Megatron. Though considering the small size of the canister and Ectotron's large metal body, the Ghostbusters concluded that the slime would work best inside of Ectotron. After Optimus Prime was able to knock the possessed scientist onto his back, Ray clambered onto his friend's chassis and administered the mood slime orally. Shortly afterwards, Megatron's ghost was expelled and Ectotron was left feeling disgusted. Doubly so given that Transformers were not physically capable of regurgitation. Ghosts of Cybertron Part 5
