While I was on Facebook and I was able to find the video on YouTube ^^ It's a really awesome crossover of Smash Bros. and Soul Eater!!!
It's the same song from Soul Eater's opening but it's sung by other people :) I have to say, it's really good ^^
The video is by:
The vocals are:
Somehow I am unable to get the link to their channels but if you are ever on YouTube, check out their channel (they have cool videos!) ^^