This started out as a small, papery tube hanging from the soffit. It kind of grew. A lot. The critters you see are called bald faced hornets. They chew on wood and turn it into a paper-like construction material. You can see that different kinds of wood make for very interesting strata lines.
Despite the fact that these buggers have built a nest right by our garage, we haven't had any problems with them. After it gets cold, the wasps with eventually leave and/or die and won't come back, so we can knock this down. I'm really curious to see what it looks like inside!