Happy Christmas, Mega Man! (ハッピークリスマス、ロックマン！) is the first short in the Otaka Mega Man Shorts series. It was released on YouTube and NicoNico on December 1, 2014.
Mega Man and Otaka are arguing over who will bake Christmas cookies. Otaka looks out the window, and sees that snow is falling. She reminds Mega Man that today is the Christmas party in Monsteropolis. The two go outside and happily skip into Monsteropolis.
Reimu Hakurei arrives, telling the citizens of Monsteropolis that she organised a Christmas concert for them. The citizens watch the concert, which is a performance by Miss Roll and her band ROLL. Everyone hates Miss Roll's new song. Metal Man shoots Miss Roll after her performance.
After the concert, Reimu comes up on stage and introduces herself. She says she is a shrine maiden and that her hometown was too cold to live in, so she moved here until the climate was safe again. Reimu then tells everybody to have fun, as "tonight, we'll never live it down!". The citizens start dancing.
When the party is over, Reimu gives out gifts to the citizens, including Mega Man and Otaka. The pair head home and open the gifts, which are a new Buster Core and a new 3DS game, respectively. Mega Man bakes Christmas cookies, and he and Otaka eat them as the short ends.
- "Winter in Monsteropolis", sung by Mega Man and Otaka as they head out to Monsteropolis.
- "KAZE yo, Tsutaete...", sung by Miss Roll in the Christmas concert.
- "Maiden's Capriccio", sung by Reimu as the party is going on.
- This short is the first short in the series.
- This short marks the first appearance of the "Roll dies" running gag.
- The song "KAZE yo, Tsutaete..." is from Mega Man: Battle & Chase.
- The song "Maiden's Capriccio" is from Lotus Land Story, the fourth Touhou Project game, released on the NEC PC-9801 in 1998, with added lyrics.
- Reimu is basically the Mega Man equivalent of Santa Claus.