From the Story
"Vincent Crabbe is one of Draco Malfoy's friends at Hogwarts, a thickset and extremely mean-looking boy with a pudding-basin haircut. He and Gregory Goyle are usually seen flanking Draco Malfoy, like bodyguards."
Discovered in Book 2, Chapter 12, The Polyjuice Potion
"Like Goyle, Crabbe is tricked by Harry and Ron into eating cakes laced with a Sleeping Draught. Harry and Ron bundle Crabbe and Goyle into a cupboard, taking some hairs and stealing their shoes in preparation for using the Polyjuice Potion."
Discovered in Book 3, Chapter 6, Talons and Tea Leaves
"Crabbe attends the Care of Magical Creatures lesson and, alongside Draco Malfoy and Gregory Goyle, works with Buckbeak. When the Gryffindors blame Draco for Buckbeak's attack, Crabbe and Goyle turn threatening."
Discovered in Book 3, Chapter 13, Gryffindor Versus Ravenclaw
"Crabbe helps Malfoy, Marcus Flint and Goyle in the attempt to sabotage Harry at the match, pretending to be a Dementor. He is given detention when they are caught, and has fifty points taken from Slytherin."
Discovered in Book 3, Chapter 14, Snape's Grudge
"Crabbe accompanies Malfoy and Goyle to the Shrieking Shack. Along with the other two boys he is splattered with mud by an invisible Harry while Ron looks on in hysterics. While Crabbe is blundering around, trying to locate his attacker, one of his big feet gets caught in Harry's Cloak, revealing Harry's head. Along with Goyle and Malfoy, Crabbe runs back down the slope towards Hogsmeade at breakneck speed."