The air was ripe with energy. Harry had been flinging around a lot of spells in a short span, an exhausting display of magic even for a wizard of his calibre. But the Winter Mantle gave him a boost so he wasn't feeling the effects of it yet. Sif was yelling something, pointing, in the din of noise and confusion it took Harry a second to see what she was getting at.
She was pointing at-
Oh.
Right.
Okay.
Think fast, Harry. Acid, explosions, energy in the air. The mechanics of the creatures nearest him were shorting as the magical waves overwhelmed them, but even as they backfired and stumbled it didn't stop the waves of their fellows from coming in behind them. They needed another moment, another pause to advance their own march forward before they got buried under the corpses of their enemy.
Harry leaped over a pile of disjointed fleshy robotics, "Parkour!" and came up rolling on the other side before he ducked then brought himself up closer to his target. Throwing his left arm out in a half circle, Harry swiped the rampant energies from the air then switched his staff so he could throw out his right hand, "Fulminos!" and release the energy in a blinding bolt of lightning from his palm. It arced across the distance in a flash and struck the creature true. Tiny racing bolts of energy raced up over its body and the creature twitched and jerked then burst like a giant, gelantuous bug.
Harry hit the deck on both knees and shouted "Ventas veloche!" and the mist of acidic blood that burst from the creature turned into acidic fog instead.
Too close. It burned across the back of Harry's hand, stopped by his duster as it ate into that instead of flesh. Gritting his teeth, Harry pushed up, dodged backward and went with the momentum as he tumbled for cover.