Prickly
"I'll help fix it," Sarah declared, "but how could I have possibly caused this?"
"A drop of blood, and an unfortunate fairy. Your plague progressed slowly. I failed to notice, failed to find the cause, until far too late."
Sarah searched her memory.
"The only fairies I saw were at the entrance when I first got here. Hoggle was exterminating them, anyway." The hair at the nape of her neck prickled. "And one bit me."
"You are not the first mortal to bleed Underground, but you were the first and only to change the rules and seize your own power."