Captain Underpants and the Attack of the Talking Toilets by Dav Pilkey
Not so long ago, George and Harold created the greatest super-hero in the history of their school - and brought him to life by mistake! Meet Captain Underpants! His true identity is so secret, even he doesn't know who he is! But that was only the start! Now the boys have accidently created a whole army of evil, vicious talking toilets intent on taking over the world!!!! This is DEFINITELy a job for the world's ONLY super-hero with WEDGIE POWER!