A cover of OnyuuP's boom song Heart Sutra Pop with only UTAU voices and no backing instrumentals. Not sure if this can actually be called acapella, though ^_^;; Also on Nico.
Voicebanks used:
Main vocal: Todoroki Eiichi
Chorus: Suiga Sora, Tsuine Owata, Shigure Nao
"Instrumentals": Defo-Imouto, Defota, Defoko