Without a wand, without even his right hand, and without an incantation, Snape had cast Sectumsempra silently and without warning. The razor-sharp magic reached Black Ginny in an instant.
Black Ginny narrowed her eyes, her expression changing abruptly, but her reaction was unnaturally swift.
She sprang hard to one side, dodging Snape's Sectumsempra, but a tree a few paces behind her, thick enough to encircle with both arms, was silently severed.
The tree crashed to the ground, its cut surface as smooth as a mirror.
"What powerful magic. And a spell I've never seen before, too. You can even cast it silently and without a wand. Impressive." Black Ginny looked at Snape in astonishment and praised him:
"Professor Snape, you really are full of surprises."
Snape snorted coldly without speaking. His response was to raise his hand again.
He cast again, still silently: Sectumsempra.
As a powerful piece of Dark Magic he had developed himself and refined many times, Sectumsempra was a spell Snape knew intimately. It was also one of the few powerful spells he could cast without either a wand or an incantation.
It was precisely because he had this trick up his sleeve that, despite losing his right hand and wand, he had not truly panicked and had even tried to draw information out of his opponent.
Yet Black Ginny's sensitivity to magic surpassed his imagination.
Black Ginny actually dodged successive casts of Sectumsempra, despite there being no sign of them to detect. Though her evasions were somewhat ungainly, she did indeed avoid them.
Dodging Sectumsempra sent a chill down Black Ginny's spine as well. She had never seen this spell before, but judging by its power, it was formidable indeed. Taking a hit from it would be no laughing matter.
Alarmed, she fired off a spell