The 130-Storey Treehouse by Andy Griffiths

Andy and Terry have added 13 new levels to their treehouse and now it's even more out of this world than before! There's a soap bubble blaster, a GRABINATOR (it can grab anything from anywhere at any time), a time-wasting level, a toilet paper factory (because you can never have too much toilet paper), a room full of mechanical grandparents, a super long legs level, an extraterrestrial observation centre and the best bookshop-in-a-treehouse-in-a-tree-in-a-forest-in-a-book in the whole world! Well, what are you waiting for? Come on up!