Sirius' popularity was not universal, however. Early on, a mutual hatred sprang up between James Potter and Severus Snape. Sirius actively supported James, leading to Snape bestowing an equal and life-long grudge upon Sirius, which resulted in Snape's happiness after Sirius' death. Sirius later claimed Snape was "this little oddball who was up to his eyes in the Dark Arts" from Snape's first moments at Hogwarts, though there is no evidence of this during their first meeting. It could be that Sirius was exaggerating this to demonise Snape. He was one of the many people who hated Snape. Sirius and James often went out of their way to bully Snape; while watching one of Snape’s memories in the Pensieve, Harry saw Sirius and James physically bully him simply out of boredom. Sirius attempted to justify this by pointing out that he and James were only 15 at the time (to which Harry hotly replied, "I'm 15!"), though he did admit that he and James were "arrogant little berks", and that he was not proud of his behaviour, but had done nothing to rectify it. He and James eventually ended their campaign of ill treatment towards Snape, but they apparently never apologised. The only time James ever stopped was in front of Lily Evans a pretty red-head, whom James later married straight out Hogwarts. Early on in his Hogwarts years, Sirius played a potentially lethal practical joke on Snape. He informed Snape of how to enter a tunnel under the Whomping Willow that would lead to the Shrieking Shack where, unknown to Snape, Remus Lupin was confined during his transformations into a werewolf. Snape went there during a full moon, and James was forced to rescue him. Sirius excused his own actions, explaining that he had simply told Snape what he wanted to know about the tunnel, while omitting crucial information. He simultaneously claimed it "served Snape right." The resentment Snape felt for Sirius was never healed. Snape was not the only student whom Sirius and James tormented during their years at Hogwarts. They also used an illegal hex on a boy named Bertram Aubrey that caused his head to grow twice its original size. It is unknown why they hexed him.