Ricky Ricotta's Mighty Robot (2000) is a children's novel written by Dav Pilkey

Dav Pilkey

David "Dav" Pilkey was born on March 4, 1966, is a popular author and illustrator of children's literature. Dav Pilkey is best known as the author and illustrator of the Captain Underpants book series. He also uses the pen names, George Beard and Harold Hutchins...

 and illustrated by Martin Ontiveros, the first in the series of books.

Plot

Ricky Ricotta was a lonely mouse

Mouse

A mouse is a small mammal belonging to the order of rodents. The best known mouse species is the common house mouse . It is also a popular pet. In some places, certain kinds of field mice are also common. This rodent is eaten by large birds such as hawks and eagles...

 who lived in Squeakyville. Once he started school,he got bullied. The villain, Dr. Stinky McNasty created the robot to destroy Earth, but the robot refused. Dr. Stinky McNasty zapped the robot. Luckily Ricky was watching. He smashed the gun. When the robot saw what Ricky had done, the robot became Ricky's friend. Together they defeated Dr. McNasty. Their motto is, "That's what friends are for."

Trivia

• The book was originally called "Ricky Ricotta's Giant Robot." However, it was changed because he is only about 12 times taller than a mouse. Ricky and the Robot are comparable to Jimmy Sparks and Gigantor
  Gigantor
  Gigantor is an American adaptation of the anime version of Tetsujin 28-go, a manga by Mitsuteru Yokoyama released in 1956. It debuted on U.S. television in 1964. As with Speed Racer, the characters' original names were altered and the original series' violence was toned down for American viewers...
  
   or to Johnny Sokko and Giant Robo
  Giant Robo
  is an original video animation series written and directed by Yasuhiro Imagawa , and inspired by Mitsuteru Yokoyama's manga series of the same name....
  
  , or to Buzz Conroy and Frankenstein Jr.
• The Mighty Robot looks like the Iron Giant from Warner Bros.' The Iron Giant
  The Iron Giant
  The Iron Giant is a 1999 animated film produced by Warner Bros. Animation, based on the 1968 novel The Iron Man by Ted Hughes. Brad Bird directed the film, which stars a voice cast of Jennifer Aniston, Harry Connick, Jr., Vin Diesel, Eli Marienthal, Christopher McDonald and John Mahoney...
  
  .