A Body of Vibranium

Ultron had changed into a new body.

Its pure black Vibranium reflected no light. Every line of it radiated cold menace, like a work of art made for killing. It stood taller than before, its sleek musculature possessing a cold, mechanical beauty.

"Impressive." Its voice came from within its body, devoid of emotion, like metal scraping against metal. "You're like bacteria in a petri dish, always thinking your struggles can change something."

Thor had heard enough.

With a roar, he swung Mjolnir like a windmill, sweeping up a storm of lightning as he brought it down on Ultron's head. He put all his strength into the blow. It could have shattered a small mountain.

Clang!

The impact rang out so loudly it numbed their ears. The smell of heated metal spread through the air.

Ultron simply raised one hand and caught Mjolnir in its open palm. The violent lightning coursed down its arm and through its body like a stream flowing into the sea. Not even a spark remained. Its Vibranium body had swallowed it all.

Thor's face went rigid. It felt as though he had struck a bottomless sponge. For the first time, his vaunted divine power had met with no response. The sensation of it being swallowed sent a chill through him.

"Pointless anger," Ultron judged, its electronic eyes flickering. With a twist of its wrist, it hurled Thor away, hammer and all, into the distant ruins.

Hulk arrived from the other side.

"Roar!"

His enormous palms, each carrying enough force to flatten a tank, closed in from opposite sides to crush Ultron into paste.

Ultron did not dodge.

Boom!

The shockwave ripped a layer of earth from the surrounding ground.

Hulk's palms struck Ultron squarely on both sides of its head.

But its head did not burst