Harry the Poisonous Centipede — Lynne Reid Banks

MEET HARRY
Harry's mother warns him of the terrifying dangers lurking above the earth-tunnels where centipedes live. Furry-biters, belly-crawlers, flying-swoopers...But there's something even worse, and that's Up the Up-Pipe! Never, never must he venture there.

Harry's reckless friend George leads him on a scary adventure to the no-top world, from which they barely escape. Surely that's enough for Harry. But will George -- or some awful danger -- make him go Up the Up-Pipe, to the dreaded Place of Hoo-mins?