All television shows and characters mentioned hereafter do not belong to me. Apart from Noel Edmonds who lives in the hall cupboard with my hockey stick and shin guards.

A/N – This had to be written. How many fabulous television shows in the 1990s had gunge as a crucial element? Fun House was the best. But I digress – on with the show!

When Mr Rowan Webb had decided that for Upside Down Day, Fenella and Griselda were going to be teachers for the day, the two girls had immediately known what exactly they were going to teach, and more importantly, who they were going to teach it to.

The staircase rattled as the soles of their boots thundered up to the third floor dormitories, around a sharp corner and into Fenella's bedroom.

'You did bring it, didn't you, Fenny?' Griselda said, pushing her hair back from her face as Fenella rummaged in her beside cabinet. She ducked to one side as eye make up that they used for their dances came flying past her head.

'Fear not, Grizzy, I certainly did!' Fenella grinned, flinging a first year spellbook onto the floor and pulling a large tub from the bottom drawer with a flourish. Unscrewing the lid, and wrinkling their noses slightly at the chemical smell, the two girls examined the contents.

The previous summer

The idea had been born at Fenella's house on evening. Griselda had come over and she and Fenella (making full use of their time in an electrical environment) had been watching a video of one of their favourite programmes.

'I so wish we could go on that!' Griselda sighed, as the opening credits of Fun House rolled on the screen. 'It looks brilliant fun!'

'And there's the small matter of your crush on Pat Sharpe!' Fenella teased, elbowing her friend in the ribs.

'You don't mention that and I won't mention your crushes on Noel Edmonds and Stuart Miles,' Griselda said, blushing furiously.

'Anyway,' Fenella said, quickly changing the subject. 'See all the gunge?' She motioned at the slime that the four kids were rolling around in and looking as if they were having the time of their lives. 'I've been thinking that-'

'It might be a very useful thing to keep around in case of emergency?' Griselda grinned.

'How-'

'You're my best friend in the whole world – it's my job. So, how do you propose we go about making it?'

And over the course of the next two days, the two girls managed to create (in an old saucepan on the kitchen stove) their own form of the gunge so often seen in many of their favourite programmes. Miss Hardbroom, should she ever find out, would probably have a hairy canary that they spend their time in such a non intellectual way but it was a way of freedom.

'It wasn't that green when we made it, was it? And it was more than cream than jelly,' Fenella examined it their green creation.

'Oh well. It'll be easier to fling at people this way. Shall we get down to planning our lesson, Miss Feverview?'

'An excellent idea, Miss Blackwood!' Dark hair intermingled with blonde as the two girls bent over the piece of paper and scribbled away madly.

Later that day

A few hours later and the two girls were fighting to keep the Chesire-cat grins off their faces. This was brilliant! Keeping an eye on the three pairs, Fenella and Griselda noticed that Miss Drill was actually quite good at potions for a non witch. The two wizards were bickering away like they were kids and as for Miss Hardbroom and Miss Cackle...

'Right girls, we're going to test it,' Griselda smiled as she looked at Fenella. Miss Hardbroom looked apprehensively at the two girls, who seemed to be able to communicate telepathically, before eyeing the cauldron of green slime in on the desk. Her desk.

Everyone having swallowed a spoonful of the anti gunge potion, and Fenella having been duly warned about potential repercussions of such an event, she scooped up a ladle of the six month old gunge, and flung it straight at Miss Hardbroom. The idea of the potion was that it should work as if the person was laminated and the gunge should have slid straight off.

'Miss Hardbroom, I'm afraid we're going to have to take some marks off seeing as you're not completely impervious,' Fenella said, trying to be very stern and fighting a mad desire to laugh at the same time. The end result was that she ended up (inadvertently) doing an imitation of the very strict potions teacher. She knew she and Griz were going to pay for this day big time but what the hell, they were going to make the most of it.

At the end of the lesson, when all potions were tested and Miss Drill and Miss Bat given top marks, the 'pupils' filed out of the room. The two girls looked at each other for two seconds, before bursting into hysterical giggles.

They were by no means the only ones. Miss Bat had sprinted off down the corridor the moment she had got out of the classroom and when the group reached the staffroom they could hear her howling with laughter, muffled by the cupboard door.

'I warned you, Miss Cackle, I warned you!' Miss Hardbroom hissed. She was absolutely livid and normally nobody bar the head mistress would have dared to be even on the same corridor as her when she was in that sort of a mood but the effect was vastly diminished when she was covered in green lime.

'It's all in the name of good fun, Constance. And it is only for one day,' Amelia said resignedly, checking her desk drawers for the emergency cheesecake she kept hidden there for stressful occasions.

'Constance?' Miss Drill spoke from the door.

Miss Hardbroom whirled around. 'What?'

'You do know that you have a huge blob of slime on your nose, don't you?' the gym teacher grinned, before deciding that it was high time that the volleyballs needed blowing up and running off.