All Josh and Danny Phillips want to do is play in the yard with their dog, like regular eight-year-olds. Unfortunately, their crazy neighbor Miss Potts makes sure that they never have any fun. When the boys accidentally stumble on Miss Potts' secretthat she is working on experiments that change people into bugsthey find themselves in a whole lot of trouble. (They also find themselves with six more legs than normal.) Can the boys survive in the world as spiders? And more important, will they figure out how to change back into humans in time for dinner?

Príbeh dvojčiat Jura a Dana i špeciálneho prípravku na urýchlenie medzidruhovej premeny ŠPUMP pokračuje, keď im zo záhradky zmizne drahocenná vec. Ak chcú bratia zlodeja chytiť, musia sa zamaskovať. Poruke majú šialenú vedkyňu. Suseda Saša Splašená nadšene súhlasí a nasprejuje ich svojím sérom. ŠPUMP sem, ŠPUMP tam - o chvíľu majú chlapci krídla, ostrý zrak a akosi čudne ich priťahujú psie výkaly. Ak chcú vylúštiť záhadu, budú sa musieť vyhnúť mnohým nebezpečným nástrahám.

Josh and Danny let Petty Potts-their barmy next-door neighbour and scientist extraordinaire-give them a lift to school, but after a mix up with their drink and some S.W.I.T.C.H spray the twins suddenly have five eyes, ears in their kneecaps and a strange ability to chuck up brown goo. The boys must SWITCH back before anyone notices they're not in class. But school is the least of their worries-they're just a whisker away from trouble-there's a grasshopper muncher on the loose . . . Petty Potts' diary One day, I am going to find Victor Crouch-confront him-and make him confess that he stole my work and burnt out my memory. But in the meantime, as far as Josh and Danny are concerned, I will keep my promise and will never make them try any more spray or potion. Or trick them. Or bribe them. Or anything like that. Probably.

Someone nasty lives up the road - a boy called Tarquin - and he's been invited over to play by Josh and Danny's mum. The twins know that their day is going to be a nightmare but when they accidently get turned into ants the situation isn't just bad it's deadly.

Josh and Danny must go on a rescue mission to save their annoying big sister, Jenny, when she accidentally uses the S.W.I.T.C.H spray on herself and turns into a crane fly! The twins know there's only one thing for it - they'll have to change themselves into crane flies too, and try to keep their sister out of trouble. However risky . . . Can the boys resist the lure of the light bulb and stop Jenny from getting legless? And will Piddle the dog be able to resist a crunchy, bugtastic snack? Petty Potts' diary Victor Crouch's spies could be anywhere! I keep imagining that old eyebrow-less freak staring through my windows . . . But I suppose I do have to remember that sometimes I see and hear things which aren't really there. That's all part of the package when you're a genius. I will make sure Josh and Danny keep very watchful, though. Ah ha! Ah ha ha ha ha! Erm. Scary powerful laugh etc. (It doesn't really work, typed out, does it?)

Josh and Danny are on a day out with the local nature group, but when they accidentally eat a chocolate muffin laced with S.W.I.T.C.H formula, they experience the real dangers of pond life first hand. Soon the boys are beetling about in a pond, breathing underwater, and creating the most almighty stench to scare off predators. But life as a pongy pond beetle is the least of their problems-there's a mysterious stranger hanging around-and he's out to get them. Will Josh and Danny find out who the stranger is before it's too late? And can they help Petty Potts in her mission to recover all of the REPTOSWITCH cubes so she can turn them into even more exciting beasties? Petty Potts' diary I do hope Josh and Danny will come round tomorrow-they have to understand the DANGER we're all in! And of course, I really need their help. I'm sure I will manage to talk them around. After all, they both can't wait to try out being a giant python or an alligator or a monitor lizard.

Petty's back with a new kind of SWITCH spray-reptoSWITCH! The lizard formula is ready for testing, and Josh and Danny are eager to help. But as Josh and Danny are trying it out in the safety of Petty's secret underground lab, they're interrupted by an intruder's attempt to get in to Petty's house! The intruder vanishes, but there is a package waiting for Josh and Danny at home containing a marble and a cryptic clue. Will Josh and Danny find the next mysterious marble? And will they be able to work out who sent the clue, and why?

Petty Potts has vanished - at least it seems that way to Josh and Danny. In actual fact, she's just relocated her secret lab… to the very pink and very girly Princess Land! Reluctantly, the twins fight their way through hordes of excited girls dressed as fairies to the back of the shop, where a single door stands between them and Petty's new lab. SWITCH-ing into geckos, the boys have no problems getting under the door and up the walls. It's on the way out that things start to get really tricky.… The SWITCH back hasn't gone well, and although Josh and Danny have normal legs, they're giant geckos from the waist up! How on earth will they escape from Princess Land now?!

Josh and Danny have gone for a nice day out at the zoo. Or, should that be, a nice, experimental day out at the zoo? Petty's developed a new S.W.I.T.C.H. spray for snakes! And Josh and Danny are willing volunteers. Things start to go a bit wrong though when they fail to SWITCH back into boys, and are spotted by a whole class of girls on a school trip! Luckily, Charlie, an old friend from summer camp, is there to help, and the panic subsides. The trouble is not over yet though....

Two brothers, one serum, and a world of trouble!.Petty's been kidnapped! Josh and Danny have already broken into her secret lab looking for her, and now they're going to brave all her anti-intruder traps and break into her house. There's no sign of Petty, but there is a very interesting little box . . .containing the best Switch spray ever. Unable to resist the temptation, the twins head to the park to try out alligatorSwitch spray. But before they make it to the river, they're roped into being in the audience of a touring chat show, with some Very interesting guests . . .