Ununtrium

Drawn from the compacted subatomic matter of a collapsed star, Ununtrium is an incredibly rare, indestructible metal bonded to the endoskeletons of Warriors Elite to massively increase their durability.

MUX continuity
Ununtrium was bonded to the endoskeletons of Sixshot, Heretech and Black Shadow. Tesarus of the Decepticon Justice Division also possesses a number of Ununtrium-coated blades in his stomach cavity.