Slimer in the Machine

Slimer In The Machine is a Crossover fanfic written by Sheba. Set in Season 3 of Transformers Generation 1, taking place after the episode Ghost in the Machine, it starts with Galvatron being plagued by Starscream's Ghost. Earth-savvy Combaticon Swindle suggests that Galvatron hire The Real Ghostbusters to dispose of his nemesis.

"Blast it!" Galvatron screamed into the empty air, "WHY can't you leave me ALONE???!!!"
"I'll NEVER leave you alone," the all-too-familiar high-pitched voice taunted him, "NOT until I get back what is rightfully mine. How ironic that by destroying me, you ensured that I would be a thorn in your side for all eternity!!! Ah, hahahahaha!"

'"STAAAAAAAAAAARRRRRRRRRSCREEEEEEEEEAM!!!!!"

—Galvatron and Starscream

Tropes used in Slimer in the Machine include:

And I Must Scream: Galvatron, when faced with the possibility that he'll be haunted by Starscream forever.
Ax Crazy: Galvatron.
Canon Discontinuity: While Starscream's fate in the G1 episode Ghost In The Machine is not explicitly specified in later episodes, and it's highly suggested that he's the victim of a Bus Crash, he does reappear in commercials as a Pretender.
Covered in Gunge: Well, it does have Slimer in it.
Demonic Possession
Nice Job Breaking It, Villain: Galvatron shoots the trap that Starscream's being held in.
Our Ghosts Are Different
Shout-Out: The title is a reference to the name of the episode from which it was derived, which itself is a nod to this trope.