What are the black flying bugs shaped like stealth bombers and leave an ink stain?

The black flying bugs you're describing are likely "ink stains" or "ink beetles," which are members of the family of darkling beetles. They are often found in damp environments and can leave a dark stain if crushed, resembling ink. Their unique shape does bear a resemblance to stealth bombers, as they are elongated and have a pointed appearance. These insects are usually harmless and play a role in the ecosystem by breaking down decaying plant material.