What is the most _____ band/song you know?

I wouldn't really call that heavy in the true sense of the word. By heavy, I mean lumbering, filthy, weighty riffs and grooves, which overwhelm you when you listen to them, and feel like they would crush you completely if they were phyisical entities. Like what Black Sabbath introduced.

This.

Think Electric Wizard heavy

Also brutal should never be used to define music.