In 2009, I brought home a coconut shell carving from a study abroad in Costa Rica (painted like a poison dart frog on a leaf, but made of a single piece of coconut shell). When unpacking it, I noticed a small pinhole (0.5mm or less) in one of the frogs toes. A few days later, that hole was slightly larger and plugged up with sawdust. I figured it had a live bug in there, so I put it into a jar so it couldn't get out, figuring it would suffocate. Over the course of the next 6 months, that one bug slowly ate that whole thing hollow. But it did eventually die. Now my souvenir is a sawdust and bug filled paper thin (less than 0.2mm thick) carving that's too brittle to take out of the jar.
What that a powderpost beetle too?