In Harry Potter and the Sorceror's Stone, Professor Quirrell let a troll in as a diversion so he could steal the Sorceror's Stone for Lord Voldemort. However, it found Hermione Granger and attacked her. Harry Potter and Ron stopped the troll by sticking Harry's wand in its nose, and by using "Wingardium Leviosa" to lift up the monster's club and drop it on its head, knocking it out. At the end of the year, Harry and Hermione found an even bigger troll, however, it was already knocked out by Quirrell so they didn't need to fight it.