Resting on an understorey plant. At a quick glance, I initially thought it was a bird dropping. The white hairs give it the appearance of being infected with an entomopathogenic fungi, maybe as a deterrent to predators...? Definitely the most amazing cerambycid I've ever seen!

Update: this species finally has a name! The paper naming and describing it can be freely downloaded from here: https://doi.org/10.54102/ajt.iv1x5