I was surprise myself
Arianna nodded and replied, "Trust me, I was surprise myself!"
"Did you say you were surprise?"
"Yes," she confirmed, "and a terrible existence it was, too… So many people hating me, but others loving me, constantly awaiting me…"
"So… when I was surprised when you said that you were surprise, how did that work?"
"Well, I was surprise. I'm not anymore. So, when I revealed my past job to you, the person currently in my past job had to come and make you surprised."
"I see. How long is it since you were surprise? Were you surprise on my 10th birthday, for example?"
"Yes, Harry. And I'm sorry that I had to surprise you in such a way…"
"No, it was fine. I love mustard-yellow, and really I couldn't have kept anything much larger than a coat hanger in the cupboard under the stairs."
"Oh, but Harry… that was me too! You were so surprised when your previously loving Aunt threw you in the cupboard under the stairs…"
"Yes, but it's not like anything any worse than that happened to surprise me in my life…"
"Oh, no? What about that time when Quirrel took off his turban and you saw Voldemort's face beneath it?"
"That was you? I mean, it was Voldemort, obviously, but you were there?"
"Yes," Arianna said, "It was that sad event that finally convinced me I had been surprise for far too long… so I decided one last mission, where I could surprise Albus that I was still alive…"
"… YOU'RE DUMBLEDORE'S SISTER, ARIANA DUMBLEDORE?!"
Harry jerked awake abruptly.
"What's wrong, Harry?" asked Dumbledore, who had been waiting for Harry to wake up in the hospital wing.
"Your sister, Ariana… Wait… do you even have a sister named Ariana? Well… if you do, I just had a dream that she was still alive!"
"I am afraid that cannot be, Harry," said Dumbledore, as a single tear rolled down his cheek.
First sentence taken from "It must be genetic" by RegalPrincessOfMagic
Co-written by me and my brother.