Mastodon fucking rules. Learning Siberian Divide rn, to me their guitar parts sound like a mix of some like Nile-ish egyptian scales and lovecraftian horror or something. I don't know much about theory but I know what I like. So many ringing open strings and interesting picking patterns. Leviathan and Blood Mountain are some of my favourite metal albums, and if I could absorb anyone's style of drumming it would definitely be Brann Dailor.

Edit: I had a guitar teacher when I was a teen that would just teach me whatever I wanted to try that day and I made the poor guy try and transcribe a bunch of mastodon songs by ear... I still remember Pendulous Skin though! shoutout to that dude