Tomb Doom is a fresh genre. The name originated on Reddit https://www.reddit.com/r/tombdoom/. The other name is "Cavernous Death Doom Metal", so the former is much better sounding yet less descriptive. It is a music full of contradictions that work amazingly well, and for a reason. It is a combination of death metal – achieved by pushing the boundaries of metal to extremes in harshness of vocals and aggressiveness of the distortion – mixed up with speed and disturbing themes. And doom metal, which focused on slow tempos as the main goal of heaviness and a mournful atmosphere. Turns out, which was a surprisingly obvious experience, that when you play aggressively fast all the time, it doesn't feel so anymore. Same when you are slow and depressive all the time. But when you intertwine those, you will get an enormously bigger impact. The slowness and heaviness get incomprehensible when they occur right after a fast part and vice versa. But this is just a half of the formula. The cavernous element of this genre is a specific sound of deep underground tombs filled with the smell of mold, skeletons covered in cobwebs and the anticipation of primordial beasts lurking in the shadows.

My favourite Tomb Doom albums:

1) MORTIFERUM – Preserved In Torment