But I don’t think I’ve ever known such a natural at Potions!” said Slughorn. “Instinctive, you know — like his mother! I’ve only ever taught a few with this kind of ability, I can tell you that, Sybill — why even Severus —”
And to Harry’s horror, Slughorn threw out an arm and seemed to scoop Snape out of thin air toward them.

Author: J.K. Rowling