Deep within the crystalline caverns of Petropia's remnant colony on Earth, a distress signal had drawn the team underground. Vulkanus, the pickaxe-wielding detrovite, was using a sonic-drill tank to harvest rare Taydenite, destabilizing the entire cavern system.
"Get away from the gems, Vulkanus!" Ben shouted, his voice echoing off the glittering walls.
"Tennyson!" Vulkanus roared. "My new drill doesn't just break rocks; it shatters anything with a crystalline structure. Like you!"
Ben slammed the Ultimatrix. "Diamondhead!"
The crystal alien stood firm, firing a barrage of shards at the tank. However, Vulkanus laughed and activated a sonic emitter. A high-pitched frequency screamed through the air. Diamondhead's constructs shattered mid-air, turning into harmless dust. The frequency hit Ben, and cracks began to form on his indestructible body.
"I can't... hold it together!" Diamondhead groaned, falling to one knee as his arm literally fractured.
"Ben!" Gwen shouted, trying to erect a mana shield, but the falling debris separated them.
Ben looked at his cracking hand. He needed something harder than diamond. Something that absorbed the pressure rather than breaking under it. He hit the Ultimatrix symbol.
"Ultimate Diamondhead!"
The green light illuminated the dark cavern. When it faded, Ben stood taller. His armor was no longer pale teal but jagged, deep obsidian. Glowing energy cracks pulsed like magma beneath the black crystal plates.
Vulkanus fired the sonic drill again. The beam hit Ben's chest—and was absorbed into the obsidian.
"What?" Vulkanus gasped.
"Obsidian absorbs vibration," Ultimate Diamondhead's voice grated like grinding stones. He slammed his hands into the ground. "And now, I return the favor."
Instead of shooting shards, Ben summoned a 'Crystal Storm.' The ground erupted, not with simple spikes, but with complex, explosive diamond clusters. He manipulated the terrain, turning the floor into a rolling wave of black glass that swallowed the tank. With a flick of his wrist, the obsidian shards detonated on impact, dismantling Vulkanus's machine piece by piece without harming the villain inside.
As the dust settled, the cavern was silent, reinforced by the super-dense obsidian structures Ben had created.