European tube wasp Ancistrocerus gazella

This mud-nesting potter wasp is a dedicated provisioner: the female captures up to 20 caterpillars and seals them in a single mud cell to create a custom-built larder. Her offspring hatch inside and have a guaranteed food supply as they develop. As adults, they switch to nectar and honeydew. Surprisingly, males can't sting at all, and the female's sting is gentle—you'd barely notice if she stung you. They commonly nest in small crevices and holes around buildings.