Its from here    • Tom and Jerry the Movie - Nostalgia C...  
I wasn't sure if this was totally true when i posted it but now im like almost completely sure it is the original sample. The nostalgia critic link is a reupload of a 2008 video, meaning it was posted before Maretu's Mind Brand was released. If you put the song's "welcome to the mind brand!1!1" on one ear and then the nostalgia critics on the other, you can see it lines up perfectly, and if you pitch down the song's you can basically hear his voice.
This cover has the song pitched down:    • MIND BRAND／滑稽者恵  
Honestly makes me like the song more
Original caption: Found someone on soundcloud saying this were it comes from. Honestly it makes me like the song even more
#vocaloid #maretu #hatsunemiku #shitpost