Draco, though longed to be a wizard again, knew about the pain that the spell could bring. Aurors had often described that some Animagi were only half-turned so their lower torsos were still of an animal while their upper torso would be human. Without training and years of experience, normal magical folks would not be able to make a successful cast. He was not going to be Granger’s test subject. Though Granger was a bright witch, he did not want to risk going to St. Mungo’s with half a cat torso and having Rita Skeeter writing the headline "Young Malfoy in a Catastrophic State’.