She fizzed faintly, like fizzy sweets popping on your tongue, but the sound seemed to come from inside my ears. The underneath of Whizzy was all fringed today, like a jellyfish, and a blue colour was slowly taking over from the fringing upwards. Really wild and wired now, she made frantic patterns in the air, leaving bristling silver trails, like sparkler writing. Did the shapes mean anything? Could they be diagrams? I tried to move my eyes fast enough to follow, but it was no good.

She zigzagged around the room again and made a clicking noise, just like Dad’s glasses when he folds them away – exactly that soft click.

‘What do you mean?’

As if answering me, Whizzy changed from blue to star-white to milky white, and that sounds like a silly little thing, but it was amazing to see. And I had the feeling that she was trying to communicate with colours because the sounds hadn’t worked.

‘Wow, Whizzy. I don’t get it, but wow.’

Her firework smell filled the room. She shimmied towards me and fluttered her semi-circular side thingies to a panicky blur. The dust particles in the air between us lit up and shivered like tiny sparks, and I flinched automatically because, really, she was still an actual runaway horse – wonderful but deadly.

She went to the top of my wardrobe and made herself small, then shot out of there, expanded herself to the height of my bedroom and turned round slowly. She did that over and over, like something was crucial.

‘What’s wrong? Has something happened?’

I was still whispering – I’m sure I was – but the next thing I knew, Lily was standing in my bedroom doorway with the hugest of all the almighty shocks in the universe sitting on her face, and Whizzy left through the window, too late. She travelled right through the glass itself, which made a scary sucking sound. And I don’t know how I know this, but I’m sure she regretted going out that way.

At first we just stared at each other. Lily was pale – even paler than Mum – and when she spoke, her voice was tiny and wobbly.

‘What was that?’

‘Erm …’ I said, then went quiet. My brain was whirring, but my body felt numb. ‘You know that eel we’ve been talking about?’

She didn’t take her eyes away from mine. ‘That was not an eel.’

She stood in my room with her hands stuck to her cheeks, listening to me but looking like she might throw up. It took ages to tell her, because every few seconds she said, ‘I’m getting Mum.’ And I’d have to say, ‘No, please don’t, Lily!’

Then I’d explain again and try to persuade her why telling Mum right at this moment was a terrible idea, and how I absolutely must leave the house and follow Whizzy immediately.