A IOSYS classic Touhou MAD remixed to sound as if the singer, in this case Alice, is having difficulties with the words gets a charming visual re-remix, and has suddenly proven highly popular:
This is part of the “uro-oboe” (vague recollection) meme, where songs are edited for moe dojikko effect to appear as though the singer is charmingly having difficulty remembering the lyrics. Watching the videos, rather than reading the explanation, is likely more helpful in understanding this.
With 200,000 views in a few days, and even more on the original non-animated version, it is evidently a popular subject…
The original iconic song by IOSYS, “Marisa Stole a Terrible Thing” (the thing in question being Alice’s heart), for comparison purposes: