Attack on Arthur Weasley

The Attack on Arthur Weasley occurred over Christmas Break of 1995, while he was on duty guarding The prophecy regarding Lord Voldemort and Harry Potter.

Lord Voldemort's Rebirth
"Who put your name in the Goblet of Fire, under the name of a different school? I did. Who frightened off every person I thought might try to hurt you to prevent you from winning the tournament? I did. Who nudged Hagrid into showing you the dragons? I did. Who helped you see the only way you could beat the dragon? I did."

- Barty Crouch Jr. to Harry Potter

In the year of 1994, The Triwizard Tournament occurred. Barty Crouch Jr., disguised as Mad-Eye Moody, made sure that Harry Potter could get through all three tasks successfully and win, so as to get him to Voldemort so that he could kill him. He volunteered to take the Triwizard Cup into the middle of the maze for the Third Task, making the cup into a portkey. He patrolled around the maze, stunning Fleur Delacour and putting Viktor Krum under the Imperius Curse. He made Krum torture Cedric Diggory, while Harry was encountering a Blast Ended Skrewt. Harry, hearing Cedric, went to help him. The two of them took the cup, deciding that they should tie, still resulting in a Hogwarts victory.

The two were transported to Little Hangleton Graveyard, and Cedric Diggory was immediately killed by Peter Pettigrew. Harry Potter was tied to Tom Riddle Sr.'s grave, and forced to give his own blood into a potion to bring Voldemort back to his body. Other ingredients used were "bone of the father unwillingly given", (Tom Riddle Sr.) and "flesh of the servant willingly sacrified". (Peter Pettigrew's hand).

Voldemort called back his Death Eaters and discussed his failed plans that had been thwarted by Harry Potter. He then duelled with Harry Potter, but was stopped by Priori Incantatem. Harry was able to escape with Cedric Diggory's body and return to Hogwarts, alerting the world of Voldemort's return.

The Attack
Arthur Weasley was doing work for The Order of the Pheonix, guarding the prophecy regarding Lord Voldemort and Harry Potter, as the Order of the Pheonix knew that Voldemort would attempt to retrieve the prophecy once he gained a body once more. Arthur fell asleep while guarding it, and Nagini attacked him. Harry Potter viewed this through his connection with Voldemort. The rest of his dorm thought that it was just a dream, however Harry assured them that it had actually happened. Neville Longbottom went to get Professor McGonagall, and she took Harry and Ron to Dumbledore's office. Dumbledore alerted the rest of the Weasley family and made a portkey to 12 Grimmauld Place. In that moment, Harry felt an urge to attack Voldemort; this and the fact that he had viewed the attack made him fear that he was being possessed by Voldemort.

Aftermath
Arthur was sent to St. Mungo's and was placed on the first floor for creature induced injuries. He had to take a Blood-Replenishing Potion, because whenever they took his bandages off he started bleeding profusely. Trainee Healer Augustus Pye suggested using stitches on his wounds, which did not work and only dissolved. However, he eventually made a full recovery and was sent back to Grimmauld Place.