Most things Nate pretends to be, I can sort of understand the logic to. Even, if he's pretending to be non-living thing, usually it's the moving sort that would fun to be, like a dump truck or excavator. On rarer occasions he might be something inanimate, like a bridge or a road, but at least those are sort of exciting, because moving things drive across them. I didn't have any answers though as to why, when I was getting him ready for bed the other day, he exclaimed, "I a pile of dirt!" Seriously?
Anyways, I went a long with it, claimed to be a front-end loader, and scooped him up with my arms, made beeping sounds as I backed out of the bathroom, and dumped him (literally) into his bed. This of course was met with great delight. As I tucked him in for bed, he added, "This is a dump truck (pointing at his bed), the blanket keeps the dirt from flying out."
Then, as he has done every subsequent night that he's pretended to be a pile of dirt, he insists that I pray for "this dirt" instead, whenever I get to the part in the prayer where I thank God for Nate.