Dav Pilkey 
Capt Underpants and the Invasion of the Incredibly Naughty Cafeteria Ladies from Outer Space [EPUB ebook] 

Harold and George’s crazy creation is back — in an adventure that’s WEDGIER than ever! He defeated the diabolical Dr Nappy… He terminated the terrible talking toilets… But is Captain Underpants ready to take on three massive, tentacled space aliens (in disguise)? And has he finally met his match in a battle with the Giant Man-Eating Dandelion of Doom…?