Piles are a type of container made with heaps of materials enclosing potential treasure within. The materials the piles are constructed from vary. Most piles do not contain traps. Rat's Nests are junk assembled by rats, which quickly scurry away when their home is torn apart. Skullpiles are heaps of skulls most likely put there by demon after they extracted them from the human heads that had contained them. Perhaps the loot was stashed away there by whatever demon was stacking them.