Skip to 1:30 http://www.youtube.com/watch?v=qgpDXZP3kZs
Sounds exactly the same as in your video. Plus, he says "I will consume all" in RumbaLumbas video, which is exactly what the Negativitron does.
Sounds nothing like Uka Uka: http://www.youtube.com/watch?v=njl6dOGkfWc
Skip to 2:00 mark. It's dead on =[ Negativatron.. I don't like it
Scrath. It's very close. There is a lot more bass in the boss