Gillyweed is not nice to eat.

"Anita, this means we're going to be practicing for an hour,"I said,"we have to be underwater for an hour, we won't be able to breathe outside of it - these gills - ugh!"

We both dove into the Drop of Doom. Anita looked impressive as a mermaid, swimming around. The Gillyweed was a lot more useful than I'd imagined. We could see underwater really well, and swim through with ease. Not having to worry about running out of oxygen was the best part. I watched Anita showing off, and decided she was ready. Her webbed feet worked really well with the mermaid tail she had made, and she was able to swim faster than me. I tried speaking to her underwater, but it seemed impossible, so we both surfaced above water.

"I'd say you're ready,"I tried to remark, but I discovered, under the effects of Gillyweed, I couldn't speak outside of water either. Trying to speak when I had no breath, first of all, and I'm not sure if it was because of the gills on my neck, but came out sounding more like some kind of screech.

Anita screeched something too, and I realised she was pointing (with one webbed hand) to some reeds close to the shore, in a shallow part of the lake.

It was now more difficult to see above water, than it was underwater, everything looked warped and blurred.

We returned underwater. I couldn't see anything. Anita cautiously swam over there. It was really shallow. When I tried to follow, I was scraping the mud on the lake bed and the cloudy, muddy water was becoming impossible to see through. I popped my head up above water, momentarily. Even though I couldn't see very well outside of the water, I recognised an oddly shaped rock, and realised it was a familiar part of the shore.

There was a path going along that part of the shore, that, last Autumn, we'd named Wise Wizard's Walk. There is a story behind its name. Ed had thought he'd spotted something golden in the water. We'd tried to fish it out, but it had gotten too late, and we had to head back to the castle. We were going to leave the stick with the hook (Accio hadn't worked and we didn't know any other spells that might) by the side of the lake, but Ed picked it up, and, as he walked off with it, using it as a cane, and striking a pose like an aged wizard on a pondering walk, he told us, solemnly,"never leave the tools by the treasure,"as he went.

We've called it 'Wise Wizard's Walk' ever since. Though we never did find out what that golden thing under the water was.

I quickly dived back underwater again, as I needed to breathe. The water was still full of churned up mud. Not at all pleasant. Anita was now swimming back towards the Drop of Doom. She was holding something. I swam after her. The water grew clearer as I swam out of the shallows. Anita spun around and showed me what she was holding, clumsily, between two webbed hands. It was a perfectly round, golden ball! Suddenly I wondered if that had been the golden thing Ed, Jared, Lotty and I had seen last Autumn. Maybe it was?

Anita passed it to me to hold. It seemed quite heavy, even underwater, and it was difficult, as I didn't have normal hands. I passed it back to her, and as I did so, I thought I saw a suspicious looking creature disappearing into the weeds on the slope of the lake bed behind Anita. I suddenly remembered Grindylows, but didn't know how to warn her. I waved at her and pointed into the weeds. She shook her head at me and pointed back to the place from where she must have retrieved the object. I realised she thought I was asking her where she had found the ball, and didn't realise I was actually trying to warn her about something.

Then Anita swam up to the surface, towards the Drop of Doom's jutting rock. She carefully launched the ball into a shrub near the water's edge, then dived back down into the lake. I realised she was planning on coming back for it later. We still had about 45 minutes of Gillyweed left. I kept a sharp lookout for any Grindylows that could be lurking around, hiding in the weeds. Anita then pointed in the direction of the large rock cliff Hogwarts is built on, above the lake. I nodded.

That was when I realised a problem with Anita's plan. A little thing that I'd overlooked too. The windows of the Slytherin common room look out into a pool of water in the cliffs above the Black Lake. The water pours down from there in a waterfall into the lake.

We both watched the great waterfall pouring down, frothing around us. I had an idea. I got my wand.

"Accio broom!"I tried to say, it just came out as a screech again, but it worked.

It flew into my hands, and I ducked underwater briefly, for more, I was going to say 'air', but, well, to get my breath back.

Anita seemed to realise my plan. I surfaced again, got on my broom (it was more difficult than it sounds), Anita put her arms around me and held on, and we sort of - flew - up the waterfall. It wasn't a very pleasant experience. At one point, I started to hope I hadn't made a very big mistake, but we reached the pool at the top. I left my broom on some rocks outside of the water.

Now we had half an hour. I decided to stay away from the windows, because if anyone saw me swimming around underwater too, it would spoil Anita's prank.

Stolen story; please report.

I nodded to Anita. She swam off, her extremely long, Rapunzelesque hair following her in a train. She didn't look exactly like a genuine mermaid, but she certainly looked very much how people would imagine one to look. Especially if they saw her. I wished I could see what happened when she went up to the windows, but I stayed as far away as I could, keeping over that far side of the pool, trying not to get pulled over the edge of the waterfall by the strong current.

I started to realise, after she had gone, that this was actually quite difficult... I was exhausted by the time Anita swam back to me. She was grinning, and I could tell just by looking at her, that the prank had been a success! I pulled myself onto the rocks, grabbed my broom. Anita held onto me again, and this time we flew down the waterfall! This ended up being worse than flying up it had been! Though, I'm not sure why. Maybe because I was trying not to go down too fast, being pushed by the water, and because I was feeling so exhausted.

Soon we were out of the water, the Gillyweed had worn off and we were sitting on the beach by the jutting out rock.

"How did it go?"I asked Anita.

"It was amazing!"Anita said,"I got to see the common room from outside the windows, instead of seeing outside the windows into the outside!"

"Did anyone see you?"I asked.

"They didn't notice at first,"Anita said,"I had to keep swirling around outside the windows. It wasn't until I pressed my face up close, that I managed to get someone's attention - and it was Jared!"

I burst out laughing,"Jared!"

In all these plans, I hadn't thought of including the others.

"Yeah, he got such a shock! And I think he recognised me,"Anita said,"then he started shouting - I couldn't hear him though. Loads of others started crowding round the windows, staring at me and pointing. I was waving and swirling around. I saw Eric and Martha, they were both eating food while watching. They didn't look very surprised, they were acting as though it was a completely normal thing to see. It was the older ones that were the most shocked!"

"If it was the older ones that were the most shocked, then your prank has certainly succeeded,"I congratulated her.

Suddenly Anita remembered the golden ball she had found. I had completely forgotten about it. She began to rummage around, looking for it.

"Is it still there?"I asked.

"Yes, here it is!"she said, pulling it out and showing it to me.

It was a lot easier to hold it now, in proper hands. It was heavy, seemed to be made of gold, though I'm no expert in precious metals. I wondered if it was some kind of magical object. I still wondered if it was the golden thing we'd seen in the autumn.

I placed it on the ground and drew out my wand.

"What are you doing?"Anita asked.

"Accio ball!"

The ball remained where it was. This answered two of my questions.

One - yes, it did seem to be a magical object. Two - it very likely was the golden thing we had seen, as it had been found in the same place and we had been unable to summon that with 'Accio' too.

"You should be careful with that,"I warned,"it might have some secret magical power that we don't know about."

"Then I'll make it my quest to find out what it is,"Anita responded.

I cast 'Revelio' and nothing happened.

It seemed harmless, but with magical objects, you never can tell.

"You should keep it outside,"I advised.

Anita reluctantly agreed. She looked around for a place to hide it. Then we returned to the castle and went down to the common room.

"Where've you been?"Jared greeted us,"there was a mermaid outside the windows, and it looked a lot like Anita!"

"That's because it was me!"Anita answered, grinning.

"I thought it looked like you!"Jared exclaimed,"how on earth did you do it?"

Anita nodded towards me,"I had a little bit of help."

"You devious, little swines!"Jared said, sounding impressed.

"Ed helped too,"Anita added, then she said,"I found something."

"What?"Jared asked.

"A golden ball,"Anita went on,"Cathy thinks it's magical."

"I'm convinced it is,"I said,"it can't be summoned with Accio, so it must have some protection spell on it, or some kind of magical properties."

"Where is it? Can I see it?"Jared asked.

"It's outside,"I answered,"it could be dangerous, so I told Anita to keep it outside. We'll look at it tomorrow."

All of the students in the common room were talking about the mermaid. They weren't paying any attention to us. Anita found Eric and Martha.

"I heard you saw a mermaid?"she said.

"Yeah,"Eric answered casually,"you know. Nothing I haven't seen before."

"I've seen loads of mermaids already,"Martha put in.

"I've seen about ten,"Eric went on,"Martha's seen less."

"I've seen more than you!"Martha argued.

Anita stared at them, shocked. She walked away while they still quarrelled about how many mermaids they'd seen.

"Such liars!"she said to me.

No one, apart from Jared, had recognised the mermaid as Anita. Everyone seemed convinced they'd seen a real one.

Next day:

After classes, as soon as we were all free, the 5 of us went down to the Golden Ball Beach (as we now call it) to examine the object.

Ed tried two types of revealing spells.

"Any ideas?"I asked him.

He shook his head,"I've never even heard of anything like this,"he said.

"Do you think it's made of solid gold?"Jared asked.

"Some of it seems to be gold,"Ed remarked,"but there is also something strange about it, something else. It would be heavier if it was all solid gold. I might be able to find something out in Alchemy Class."

"If you do, make sure you tell us,"Anita said.

"Look what I've found!"Lotty called over to us, suddenly walking out from a small thicket of trees, grinning and holding up and old stick with a large, rusty metal hook on the end.

"I can't believe it's been there all this time!"I said.

"What is that?"Anita asked

We described to her, in detail, the time we saw the golden thing. She'd only heard a brief account of it before.

"Now I know why you call that path 'Wise Wizard's Walk',"she said,"I never knew it was named after Ed!"

"What? You thought it was named after an actual wise wizard?"Jared laughed.

"Ed is a wise wizard!"Anita objected.

"Yes, Jared,"said Ed,"I am wise. You should heed my councels."

We didn't discover anything new about the object.

People are still talking about the mermaid seen from the common room. Anita tried telling them it was actually her, but no one believes her. Her prank has gone a little bit too well...