Monster Blood for Breakfast! by R. L. Stine
Fright-master R.L. Stine invites you on an all-new, all-terrifying adventure! When Matt ordered a container of Monster Blood from a weird website, his only intention was to play a harmless practical joke. But the joke's on him--and so is the mysterious green ooze. He's even eaten some of it! As if Matt's problems weren't big and slimy enough, an invitation to HorrorLand is also on its way. Can Matt and his sister survive inside a terrifying scream park where trouble lurks behind every turnstile? Can YOU?