Kimagure Mercy (気まぐれメルシィ) is an original song by Hachioji-P. It tells the story of a girl (Miku) who is sick of dealing with a man who is shallow, and only interested in her when he wants something from her.
This song entered the Hall of Legend and exceeded over 10 million YouTube views. Hence, this Hachioji-P’s most notable song, and one of Miku’s most notable songs.
EDIT: Fixed a stupid mismap where I miss clicked a block -.-