Harry's first task is to collect the golden egg from a Hungarian Horntail Dragon. Charlie Weasley describes the Horntail as a "vicious thing" whose "back end's as dangerous as its front" because its tail has spikes protruding every few inches.
33) How does Rita Skeeter find out secrets about the Hogwarts students and staff?
Harry and Cedric decide to end the Tri-Wizard Tournament in a tie by taking the Tri-wizard Cup together. The cup is actually a portkey, which Voldemort uses to bring Harry to him. When Harry and Cedric both appear, Voldemort has Cedric killed.
Dolores Umbridge is brought in by the Ministry of Magic as the Fifth Year Defense Against the Dark Arts teacher to convince the students that Voldemort has not returned and there is no reason to teach defensive magic.
A curse was placed on Marvolo Gaunt's ring, which Voldemort was using as a Horcrux. The curse was designed to kill anyone who wore the ring, but Snape managed to temporarily contain the curse to Dumbledore's hand.
40) When Dumbledore and Harry first visit Horace Slughorn, what is he disguised as?
When Dumbledore visits Horace Slughorn to try to convince him to be the new Potions professor, Slughorn pretends to be an overturned armchair in his apparently ransacked house to try to convince Dumbledore that he is not home.