This is the theme that plays when Goku transforms into Super Saiyan 3 (aka. SSJ3) on popular anime series Dragon Ball Z. It was composed by Bruce Faulconer, an American composer and the primary author of the music featured in the Funimation dub of the DBZ. There are many of covers of this on Youtube but most of them sound pretty bad. I noticed that there were a lot of wrong chords and weird rhythm patterns so I decided to try to play it myself better. In this video you can see the result. It's mostly improvised but some of it is premeditated (e.g. the intro). I think it's not perfect but it will do. Enjoy the video and please, tell me what you think of it! :) P.S. And for those who are interested: I'm not using a clear piano sound. I used the dual mode on my keyboard and added some synth sound under the piano sound to make it cooler.