Tironium

'Tironium is a substance from the Beast Wars portion of the Generation 1 continuity family.

Tironium is, presumably, an extremely tough substance.

Fiction

Beast Wars cartoon

Upon observing Terrorsaur after he absorbed unstable energon into his superstructure from the flying mountain, Rattrap commented that, with his newfound power, the Predacon looked like he could "eat tironium". Power Surge