MUD DAUBER WASP NEST

... in my shed, which is build from mud. Next to it I also had a few 'organ pipe mud nests' on a stool in the shed.
The females build the nests, and hunt to provision them with a spider. To capture a spider, the wasp grabs it and stings it to paralyze the spider and takes it to the nest. A  mud dauber lays its egg on the prey and then seals the nest. The young survive the winter inside the nest. They cram as many spiders as they can into the nest cell.
These wasps do not sting, they drink flower nectar and the blue mud dauber is the main predator for the black and brown widow spiders. So I will keep the nests in my shed!