Revolio Clockberg Jr. (better known as Gearhead) Rick usually treats him like a glorified tech support line. His lore is a mix of tragic planetary history and some very questionable choices in friends.
Here is the "gear-based" breakdown of his lore:
The Gear Wars: Gearhead is famous (or infamous) for his obsession with the Gear Wars. He will explain the entire history to anyone who listens—even though Rick finds it incredibly boring. According to him, it wasn't actually about the gears; it was about the transition from the gear-based economy to a more digital one.
The Betrayal: In the Season 2 episode "Morty Night Run," Gearhead betrays Rick and Morty by calling the Galactic Federation to arrest them. He did this in exchange for "top-tier" gear parts. Rick, being Rick, anticipated this and neutralized Gearhead by ripping off his "gear-sticles" and attaching them to his mouth.
The Gear-sticle Incident: This became a defining (and painful) part of his look. For several appearances afterward, he had to live with his "gears" on his face, which made him even more of a laughingstock in Rick’s eyes.
Talents and Interests: Despite being a traitor, he is a genuinely talented musician. He was the keyboardist for The Flesh Curtains (Rick and Birdperson's old band) and is often seen at alien festivals and parties.
Physiology: He belongs to a race of sentient gear-people. Every part of his body—from his internal organs to his "private parts"—is a functional mechanical component. This makes his anatomy a recurring joke, as Rick frequently insults him by calling his parts "garbage" or "low-end."
He’s currently back on "shaky" terms with the group, mostly because Rick finds it easier to bully him than to find a new mechanic.