Big in Japan is the 20th episode of Uncle Grandpa Season 1, and the 20th overall episode of the series.
When Uncle Grandpa and friends help Akira make a monster movie, Mr. Gus sees it as a opportunity to show off his acting skills.
The episode starts off with Akira trying to shoot a monster movie using his toys. This did not work out for his artistic tastes, so he quickly becomes frustrated. The UG RV crashes into his living room before Uncle Grandpa, Pizza Steve, and Mr. Gus step out to greet Akira. After a rough greeting, Akira tells them how he wants to create a monster movie but has no monster to film for it. After a bit of arguing, Mr. Gus volunteers. Before they could do anything else, however, Uncle Grandpa forces Mr. Gus to eat a pill that makes him become giant.
The shooting for the movie began and the first scene was the monster's rampage. Mr. Gus tries to envision a theatrical scene of what would cause the monster to go on a rampage. Before Mr. Gus can even think about it, Pizza Steve and Uncle Grandpa tickle his feet with giant feathers that cause him to stomp around the city recklessly. The next scene was a scene where the monster breathed fire all over the city. Again, Mr. Gus tried to come up with a theatrical scene, but Uncle Grandpa forced him to drink hot sauce which caused him to carelessly shoot fire at random buildings all over the city.
The next scene was the monster death scene. Again, Mr. Gus tried his best to create a theatrical and dramatic scene for the monster's death, but Pizza Steve decided it would be a good idea to shoot him with a rocket launcher instead. After Pizza Steve shoots Mr. Gus, Akira announces that he has all the footage he needs to make a monster movie. Unfortunately, Mr. Gus was dead. They immediately have a funeral for him and mourned in the most disrespectful way they could (except for Giant Realistic Flying Tiger who gave a heart felt speech). This terrible funeral made Mr. Gus stop pretending to be dead and get up. He explained to them how he wasn't dead, but pretending to be dead for the movie. They all think he is a zombie rather than believe what he's telling him, so they chase him around with a chainsaw. The episode ends with them watching Akira's movie and Mr. Gus wrapped up in a full body cast.
- This the second episode where Belly Bag has a non-speaking role in it. However it's considered the third time if you count the original pilot.
- This episode parodies the Godzilla franchise.