|This article is about a/an episode in Juken Sentai Gekiranger.|
Hapi-Hapi! Merry Christmas, Osu is the forty-third episode of Juken Sentai Gekiranger.
Ken and Master Pyon Biao try to figure out the reason behind why an English-speaking boy hates Christmas and deal with a tricky Genjuken warrior.
While Christmas shopping, Ken and Bion Biao meet a young American boy named Carl who hates Christmas. But Ken, misunderstanding Carl, brings him to SCRTC's Christmas party. Eventually fed up with everyone, Carl exits SCRTC in a hurry after knocking down the Christmas tree with Miki the only one who knows the truth. Meanwhile, Mele is thinking of a Christmas present for Rio until Long arrives with one of Suugu's Twin Phantoms, Mythical-Beast Hanuman-Ken user Shuen, sent to cause mayhem across the city with his clones to gather screams from the populance. While Ken and Bion Biao attempt to understand Carl's issues in spite of the language barriers, the other Gekirangers battle the massive army of Shuens while the real one escapes to commit arson. While it all occurs, Ken learns from Carl's father, a North Korean diplomat, that the boy's hatred for Christmas stems losing his mother in a car accident, with Ken reasoning with Carl with his similar path before Shuen arrives. While Bion Biao protects Carl, Ken transforms into Geki Chopper and defeats Shuen with the Super SaiBlade, but Shuen enlarges and the Gekirangers bring out SaiDaiOh, Geki Fire, and Geki Tohja Wolf to battle with Bae commenting while Mele is wearing a special Santa outfit for Rio. Once Shuen is frozen, SaiDaiGeki Fire destroys Shuen. Later, the SCRTC gang resume their party at Carl's house, with SaiDaiOh creating an image of Carl's mother as Ken's present to the boy.
- As part of Super Hero Time, this episode aired alongside Kamen Rider Den-O episode 46, Now to Reveal Love and Truth
- This is the fifth of seven consecutive episodes where the character themes (as sung by the actors themselves) make up the ending of Gekiranger in place of regular ending theme Tao. The fifth, Sou Iu Koto mo Aru daro yo, is performed by Sotaro Yasuda, who portrays Ken Hisatsu.
Juken Sentai Gekiranger Volume 11 features episodes 41-44: Lesson 41: Zushi-Zushi! No More, Lesson 42: Wasshi-Wasshi Moving On!, Lesson 43: Hapi-Hapi! Merry Christmas, Osu, and Lesson 44: Wafu-Wafu! Father's Melody.