The "what" has to do with the unexpected way the music goes about it. They rock or march but in an unusually primal, almost minimal way. Primal in that there are elemental intervallic drones that can combine with advanced harmonic droning chords or just trance out with rock drums beating underneath.
Megafaun is Phillip Cook (here on banjo, modified electric guitar and "moog lap steel"), Bradley Cook (electric bass, acoustic guitar and mandolin) and Joseph Westerlund (drums, percussion and electric guitar). Take that and add the "excited" string bass of Mr. Dreyblatt (I take excited to mean played by means of a motorized friction or other than with the hands in general?).
When you get to the third piece, it's multi-layered sustains without beat, cosmically irradiating like an elaborate cartoon sun. They get such interesting sounds and there is enough change within the unified structure that it is mind-bending and acoustically interesting without straying too far on either side of the both/and.
The final cut gets back into a march beat and another series of trance-beated drone repeaters.
I cannot say this sounds like anything else, except if we were on another planet and were treated to a performance of the folk-rock the "natives" had independently created? The fact that it's different is one thing. The fact that it locks together and does it all very properly indeed is another thing.
It's a weirdo winner--from all hands! Seriously.