Rheanimum
Rheanimum is a rare gas that is mined on Tykos, a moon of E'brutoc. It improves the density and durability of metals by filling the gaps between molecules, strengthening the material to near-indestructibility. Handy stuff if you're made of metal.
Fiction
Marvel Generation 2 comic
Megatron led his newest warriors (the Laser Rods and Rotor Force) to capture the rheanimum stores on Tykos, intending to use the plundered substance to render his army unstoppable. New Dawn
When the Swarm attacked the combined Autobot-Decepticon forces on Earth, the rheanimum was instead distributed among the allied Transformers, in hopes that its properties would render them invulnerable to the Swarm. It worked. However, in Jhiaxus' flagship in Earth orbit, Optimus Prime refused the rheanimum offered to him by Starscream; in order for his desperate gamble to work, he needed to be consumed by the Swarm! A Rage in Heaven!
TransTech
The processing center that provides ingress to Axiom Nexus has (among other defenses) rheanimum-reinforced walls. Withered Hope
Animated cartoon
Omega Supreme's armor is enhanced with rheanimum. The AllSpark Almanac
Shattered Glass
Octopunch was given experimental rheanimum rust-proofing to aid in underwater missions, but this had the unexpected side effect of making impervious to nanotech invasion and thus the go-to 'bot for missions against Junkions. BotCon 2012 Octopunch profile card
Timelines
Ratchet's new combiner body incorporated rheanimum into its construction, increasing his durability at the molecular level. Customization class G2 cartoon Ratchet bio
Notes
- Rheanimum is probably based on the rare high-density transition metal Rhenium.
