Time stopped.
He fell.
The green light hit him, and he fell.
Harry Potter, the greatest wizard of all, was dead.
Dobby couldn't save him.
Dobby tried.
The evil Voldie-wizard killed him, and Dobby couldn't stop him.
The elf stood paralyzed as his world fell apart.
Harry Potter is dead.
Dobby has no friend.
THEY HARMED HARRY POTTER!
In his rage, the elf—underestimated by all—slew fifty Death Eaters along with their master.
He had nothing left to live for.
In the aftermath, they discovered him holding the body of Harry Potter, eyes glowing in a righteous fury. As the few survivors of the Light gathered, his mind raced, realizations falling in line.
Now, what happened next is no simple matter. Wiser minds than ours could not unravel the hows and whys of what Dobby accomplished. We do know a few things, though:
First, Harry Potter was no ordinary wizard. When he assisted Dobby in gaining his freedom from the Malfoys, rather than bonding Dobby to himself, he left him to his own devices, a happening unheard-of since the enslavement of house-elves.
Second, Dobby was no ordinary elf. Once free of the dominating influence of Lucius Malfoy, he embraced his freedom, believing Harry's assurances of his value.
Finally, it is universally acknowledged that house-elves will do the near impossible in order to obey and serve their masters.
But their friends…?
That day, on a hill in Scotland, just outside of Hogsmeade, the strangest elf in an age formed the strongest bond in an era with the strangest wizard of his time.
And Dobby the house-elf changed time.
With a snap of his fingers, the strange form of apparition used by house-elves transported his mind back twenty years earlier, to the very moment when Lucius Malfoy threw him a bloody, battered sock.