This Nightmare was not the easy prey Ayumu expected. The specters of Mascots did not cause an iota of deviation in its gaze, slow steps drawing in closer to the home without even acknowledging them. This didn't change when the illusions turned feral and the great cats leaped towards the Nightmare to try and rake across its flanks.
The reasoning for this was shockingly self evident, as the Shadow cats melted upon contact with the miasma of darkness surrounding the beast. Not a grunt was heard, their forms dissolved before even striking the creature's hide. What magic constituted Ayumu's illusions was so paltry it made no visibly difference in the Nightmare's aura, but that was soon to change with Ami bursting forward and burying her boot into the Behemoth's face.
Four eyes flashed with acknowledgement, howling at finally being struck even as the firey Magical Girl darted back with waves of fire following in her wake. Just as the illusions were, the flames too were swallowed up by the miasma, and now it would be obvious that the cloud was growing in proportion to the magic pumped into it. It rose outwards and upwards, like the burner on a stove that tappered to a flickering bulb of ravenous hunger fuelled by the immaterial attacks.
From where Ami landed, she'd feel a sudden weakness in her leg and looking upon it would reveal patchwork holes like the left over feasting of mothes upon her Magical Girl transformation, stripping it away to glimpse the pajamas she wore moments prior. She would feel a dip in her magical reserves, stolen away to feed their adversary whose form was lost entirely in the miasma.
Apia's efforts where to fair little better, the bees more substantial then illusions and flame yet so small that they were lost to the darkness before they could complete their second revolution of its leg. Apia's warieness would spare her Ami's ill effect if she broke off from her attack, but if she continued her stinger would only secure a single strike before melting along with the garments across her arm and chest, such was the depth of its rapidly increased aura.
Then came another beastly roar, this time one of pain, as a tightly woven spear of wire tore its defense and struck the beast's hide. It melted just the same, but lasted enough for the spearhead to punch through and give the Nightmare cause to tear its ravenous eyes from Kuro and acknowledge the Magical Girls threatening it.
It followed the bellow with a great inhalation, the force of its breath pulling at the wild hair of the assembled girls as it drew in debris, detritus, and its own miasma into painfully distended jaws. The Nightmare's visage was revealed once again, bright red crag's bristling with magical power just beneath its hide. So much more then the Detention Club would harvest in a month of non-stop hunting, now crammed into one beast whose aura was condensed into a ball of ravenous intent.
Kanbaru watched the initial exchange play out with a calculating gaze, widening marginally at the ineffectiveness of their attacks up till the Club President struck a blow worthy of reprisal. At least we can be certain this thing isn't a secret speedster.
However there was little else to celebrate when she connected the dots and realized what it was planning. A surge of panic forced her to fall to one knee and slam both her hands into the ground. The front of Ami's house where the rest of the Club stood paralyzed in shock was encased in a solid sheet of ice, plugging up the broken windows with feet upon feet of blackened ice just as the Nightmare's inhalation ended.
A moment later, and it released a breath that carried the miasma in a wave of darkness surging toward the residence. The street, sidewalk, and building itself were entirely unaffected by the murky tide, but on contact the ice sizzled and melted, inches disappearing in seconds. The barrier would last precious little, but for the magical girls it would have to be enough. "Everyone, move it or lose it!"
The Code Keeper barked out, sprinting into the kitchen after Seyrun, holding the door just long enough that Tsuruga came in right after her, still in her pajamas with Kuro pulled to her chest in a death grip. The Iron Winged Magical girl was cursing under her breath, her wings too much of a hassle to transform into in such a cramped space.
There were precious few moments left before the last of the ice gave way and filled the main room with the Nightmare's miasma. To those girls still outside and away from the directed attack, they'd find the Nightmare exposed without the protection of its aura.