Justin didn't take it, because taking unknown magical items from people you didn't know was a little like taking candy from men in windowless vans. "What is it? And what spell?" It wasn't that he didn't trust Alexander, except, well, he didn't. He barely knew the boy, and their interaction so far had been less than cordial. The symbol on the bag twisted in a way that if he tried to follow it too closely with his eye, he got a bit queasy.