Herbalist and skilled potion-maker, Cora Winstanley is heading out to hunt for a bristlewurm. Specifically, she wants to milk the special green goo from the greasy two-foot-long squirmer.

But, what's so special about the goo? It has laxative properties. For example, if you've eaten too many crumpets and they're living rent-free in your bowels, a potion laced with bristlewurm goo will help with a rapid (and often explosive) eviction.

With youthful enthusiasm, Cora heads out into Oakmere forest to obtain a pint of the green viscous gunk.

Will she find a big juicy wurm in the forest?

Will she remember to rub the bristles the right way?

And can she fill her pint jar with the valuable gunk?