Voldemort always needed to do everything himself. Most of the time, he needed to do it instantly as well. The patience of Tom Riddle was gone; the long game could not properly reside in this splintered soul.
So it came that the Dark Lord began to conquer every aspect of Hogwarts.
The paintings were easily tamed and frightened, and they would direct him across the school fearfully.
The ghosts only whispered and avoided him; his power over them unspoken and unknown even to Bellatrix, Lucius, Severus.
The forest parted at his presence, the trees withered.
The spiders ran, and those centaurs who remained bent knee under his magic, though they swore his fall would be brought by Neptune.
He scoffed in their faces, and strung them up.