Walt Disney Pictures and Jerry Bruckheimer Films have paid $1.5 million for film rights to the unpublished novel “Monstrous Memoirs of a Mighty McFearless,” by first-time writer Ahmet Zappa. The story concerns a young brother and sister who learn their family is part of a long line of monster hunters. The pair squabble constantly but must band together against the most diabolical creature in the universe. The book is scheduled for publication in August from Random House as a hardcover with full-color art. Zappa wrote the story and penned some 300 illustrations.