Dear diary,

Today was the day. Mark had been all lovey-dovey yesterday, before going to meet Molly in a bloody broom cupboard. She set him up for midnight and so we prepared the Great Hall. At ten o'clock we left our dorms and went down to get it ready. There were catherine wheel canons ready at the sides of the hall and pie launchers too, courtesy of Uncle George. We had magical chains to hang him from by the ankles, and Molly was waiting in the shadows. There were even two jars of dragon piss which James had somehow acquired from Hagrid dangling above the chains. Everything was set.

Mark arrived at midnight exactly and Molly whispered seductively from the shadows. I felt a bit weird witnessing it, but the anger inside was bubbling up, and I wanted to make him pay. We watched as he began to strip off before I murmured the incantation for the chains. Instantly they flew down, clamping round his ankles, before springing back up to leave him dangling. We could hear the trickling of the dragon piss onto him.

'Molly, babe, I didn't realise you wanted to dominate...' he sounded flirty.

'I don't, Mark. I want you to pay.' she said calmly.

'What are you on about baby?' he asked slowly, as it dawned on him what was happening.

I stepped out. 'Mark, you played us, and in doing so you fell for it. We're going to bed.' I told him as the chains clanked. He was struggling. I could feel apprehension in my stomach, I felt guilt in my chest, but I followed Molly and the boys and left him hanging there, not before I hexed his head to get boils in the shape of the word: 'CHEAT'.

At 8AM when everyone would arrive for breakfast the canons were meant to go off. The doors opened at eight and everyone began to laugh and jeer when they saw Mark. Then the canons went off. Catherine wheels whirled around him and pies splattered his face. The dragon piss smelled awful, and firecrackers began to gather, spelling things like: "CHEATING BASTARD" and "FULL OF SHIT". I think that was when I realised what I'd done. Everyone must know now that I wasn't good enough for him. He tried to cheat on me with my own sister. He's a twat and I hate him, but he was hanging there in his boxers, with boils on his head and soaked with dragon piss. The people laughing and jeering didn't make me feel any better, they just made me feel mean. It hasn't made what Mark did hurt any less, and the professors must know by now who was behind it.

I expect I'll be expelled tomorrow. My dad is going to be so disappointed. I'll probably ruin his chances of becoming minister for magic and wreck his life too. That prank wasn't funny or clever, it was childish and silly. It was pathetic. Mark looked like he was going to cry, I feel stupid and guilty, and my dad will lose everything he's spent his life working for. But worst of all, it's all my fault. I expect to get a howler tomorrow. I have no qualifications, only OWLs. I've done worse than Uncle George, and Grandma will kill me. I'll never be head girl or do my NEWTs. Everything's ruined.

I can't sleep, can't eat. My entire life is hanging in the balance and it's all my fault. The worst thing today was when McGonagall saw the whole thing. Her eyes passed over James and Fred like she was angry, she looked at Molly like she was embarrassed for her, but when she looked at me, all I saw was sadness and disappointment. I've failed her as well. I'm a failure. I'm an embarrassment to my whole family, and I won't be surprised when I get expelled. I'll just try to take it with dignity...

Lucy x

A/N: oh Lucy, you've done it again! Well you know what she's like! Don't worry guys, things will get better! And you'll ind out sooner if you lovely people review ;) okay I'll shut up