"This prank," I began, "requires complete concentration."
"Why?" Fred asked.
"Yea," George added, "We're only going to slip Snape some veritaserum and ask him silly questions and post them on every spare inch of wall we can find."
"Exactly," I said, "wouldn't he remember if WE asked him the questions?"
"Oh." the twins said.
"Then how are we going to do it, oh Queen of all that is Pranks?" Fred asked.
"Simple." I said, "We disguise ourselves."
"You're not suggesting..." George started.
"Yes." I said, "Polyjuice Potion."
If you don't know how Polyjuice Potion works, it changes your appearance to whoever's DNA you put into it. It feels like your body is melting, you're going to throw up, and being stabbed with a hundred needles all at the same time. Luckily, I didn't have to use it, it was poor Fred being tortured today.
"Here," I said, "it's done. Drink it."
"Do I have to?" Fred asked, putting on his best 'pity me/puppy dog' face.
"Yes." I said, "Now drink it before he comes this way!"
"Fine!" Fred said, as he put it up to his lips.
As soon as he finished drinking it, he dropped the glass (which was only plastic, so it didn't break), and it seemed like forever before his face finally lost its last few freckles, and his hair lost its orangey-red-ness.
Before us stood Professor Dumbledore. In student's robes.
I grinned as I pulled out the pair of the real Dumbledore's robes that he had let us borrow.
Thankfully, he was very kind in letting us pull out a few of his hairs and borrowing a pair of his half-moon spectacles and robes.
"Here you go, Professor." I said, very sarcastically.
"Well," Fred (as Dumbledore) said, "Now I know what it feels like to be old. And I NEVER want to get this old."
"Maybe you won't." George said, "Now get over there, and slip him the potion!"