One of my favorites from MOSHIMO. There is also a faster paced song called Tsutta Sakana Ni Esa Yare whose MV references the last scene of this MV.
Bilibili is I think the major video streaming site in China and a number of other east asian countries, basically their Youtube. It is “legit” in the sense that it’s a major company and they also have official paid offerings e.g. for anime streaming. What it probably doesn’t have compared to Youtube is an effective copyright strike system. Whether you think that’s good or bad is up to you, but it’s probably why the song is still available there and not on Youtube. :)
That song is also nice. But the singer doing it in the same high-pitched cheery voice was a bit incongruous for me. I was kind of hoping she could also pull off a deeper voice.