After the Triwizard Tournament began, the castle received quite a few visitors, but Severus's childish desire for revenge showed no sign of restraint.
He had originally thought that after Remus, Albus would never be able to find another Defense Against the Dark Arts professor. Then Alastor Moody had popped up at this moment and ruined his "good deed" again.
With old and new grudges piled together, poor Neville had replaced Harry as Snape's primary target for revenge. He could always easily find an excuse during Potions to keep Neville, who was better at melting cauldrons than brewing potions, behind in detention.
Pomona only heard from the Hufflepuff children afterward that Neville had been kept by Snape and made to dissect an entire barrel of horned toads.
So she threw down her spatula, left the kitchen, and marched heavily and furiously toward the Slytherin dungeons.
As she passed the Great Hall, she encountered Ravenclaw's ghost, the Grey Lady.
Helena gave Pomona a reserved, proud nod, apparently considering that sufficient greeting.
Most Hogwarts ghosts were pearly white, like Nearly Headless Nick and the Fat Friar, but there were always a few exceptions.
Such as the brightly colored Peeves, the bloodstained Bloody Baron, and Ravenclaw's ghost, Helena. She was one of the few ghosts who continued studying after death.
Helena had earned the nickname "Grey Lady" because she was greyer than ordinary pearly white ghosts, and perhaps it was her insatiable thirst for knowledge that made her different.
If one day humanity truly gained the ability to live forever, but at the cost of losing all senses such as smell, taste, and touch.
When your lover touched you, you felt nothing. When fine food was placed before you, you could neither smell nor taste it. Would you still choose immortality?
Two years ago