"Power of unicorn'ss blood to presserve life makess excellent combination with troll'ss healing. Only Fiendfyre and Killing Cursse sshall girl-child fear, from thiss day."

What, not basilisk venom? In canon, that was also a way to destroy a horcrux.

I am also updating towards the theory that what we are seeing in this chapter and the last is some sort of illusion; either the mirror or hpmor!legilimency. The biggest piece of evidence against it is Eliezer's assurances that the story will not lie to us because he wants the plot to be solvable; he was very careful to point out that Draco's false memory was, in fact, false.