|"The Origins: Part Two"|
|U.S. air date:||February 15, 2016|
|U.K. air date:||February 15, 2016|
|International premieres:|| Netherlands & Africa: February 6, 2016|
Portugal: February 7, 2016
Italy: February 12, 2016
Germany: February 20, 2016
Turkey: February 27, 2016
Hungary: February 27, 2016
Japan: May 5, 2016
|Written by:|| Ben Bocquelet|
|Storyboarded by:||Aurelie Charbonnier|
| I'm On My Way
"The Origins: Part Two" is the twenty-first episode of Season 4 of The Amazing World of Gumball. It is the 137th episode overall, and the second part of The Origins.
Darwin tries to return to his family after accidentally getting flushed down the toilet.
The episode begins with a title card saying "Previously" and the narrator speaks, and several clips of past episodes were shown. Then we come back to the scene where Gumball, Richard, Nicole, and Darwin were trying to take a picture, and Darwin accidentally getting flushed down the toilet.
The episode then begins with Darwin coming out of the sewer and into the sea, meeting several other fishes. He frantically asks them how to get home. The other fish said a fish can't get far on land, but Darwin never gives up. He swims faster and jumps out of the sea, but collapses quickly on the sand due to him not having lungs.
Back at home, we see Gumball with a tear in his eye at the loss of his new friend. Nicole and Richard try to cheer him up, and Gumball says that he believes Darwin will return, going back to the scene where Darwin gets his new heart and lungs. He waves goodbye to the fish and begins his journey back home to Elmore. Across the deserts and the valleys, Darwin gets tired, but soon sees that he is close to Elmore. He runs happily, but bumps into a rock.
Back at home, Gumball is still sad, but he wished he'd kick Darwin in the butt if he gave up his journey, and we go back to Darwin, who has now grown new legs and feet. Darwin tries out his new legs amd feet, and runs all the way to Elmore.
Darwin, now happy that he is in Elmore, asks several citizens where his pal Gumball is at, only to scare them. While Nicole, Richard, and Gumball were posting missing papers about Darwin, a pest controller shoots Darwin and locks him up in a cage where the dogs were. But after he sensed that Gumball gave up, he took the key to unlock the cages of the dogs and himself, freeing himself and the dogs. Darwin then happily continues to find his family.
The Wattersons decide to get a new "Darwin", not noticing Darwin running past behind them while they drove away in their car. At the Elmore Mall, Darwin finally catches up to his family but notices that the Wattersons are about to replace him, leaving him heartbroken and sadly leaves the mall. However, just as Gumball is about to purchase a new fish, he senses Darwin's presence and realizes he's back. He runs to catch up with Darwin and they reunite outside the mall, overjoyed. Much to Richard and Nicole's joy. Noticing Darwin's bruised feet, Gumball gives him his green shoes. The Wattersons officially adopt Darwin as a member of their family and drive back home as Darwin prepares to explain how he managed to return to Elmore, ending the episode.
- Doughnut Sheriff (clip only)
- Anais (clip only)
- Chowder (DVD Episode Version Only)
- Wakko Warner (DVD Episode Version Only)
- Gazpacho (DVD Episode Version Only)
- SwaySway (DVD Episode Version Only)
- Buhdeuce (DVD Episode Version Only)
- Jelly (DVD Episode Version Only)
- Dot Warner (DVD Episode Version Only)
- Yakko Warner (DVD Episode Version Only)
- The Sun
- Eagle and chick
- Cupcake Woman
- Mr. Pepperoni
- Mr. Small
- Crocodile Woman
- Sussie's parents
- Hot Dog Guy
- Oval family
- Pest Controller
- Principal Brown
- Melted Cheese Guy
- This episode aired on the same day in the U.K. and the U.S.
- This episode was originally going to be titled "The Roots."
- This episode was the first in the series to be a 2-parter.
- This episode was mentioned at the Paris Comic Con during Ben's panel. 
- It is revealed that Darwin grew lungs and legs when Gumball gave him hope by the "Power of Love."
- The Rainbow Factory was under construction at the time of this episode.
- Teri's face was badly drawn as an infant.
- It is revealed that Sussie was quite intelligent and speaks in full sentences as an infant, but after her parents accidentally dropped her, her voice and intelligence changed as she became the way she is now.
- Clips from "The Return," "The Gripes," "The Password," "The Butterfly," "The Puppy," "The Law," "The Vacation," "The Authority," and "The Fraud" were played as part of a recap sequence in the beginning of the episode.
- The episode airs in Italy on February 12, which was chosen due to it being Charles Darwin's birthday.
- This episode is similar to the Studio Ghibli movie Ponyo, in which the main character, a fish, gains magic powers and transforms into a human to find her owner, Sosuke.
- Some cars in Elmore has every driver missing while Darwin looks for the Wattersons.
- When Siciliana Pepperoni yells "Someone call pest control," her mouth doesn't move.