Not pretty, but interesting!
The rat-tailed maggot is the larvae of the Drone fly (Eristalis tenax), a bee mimic fly that although European has been introduced to America as well as South Africa and other countries.
A characteristic feature of rat-tailed maggot is a tube-like, three-segmented, telescoping breathing siphon located at its posterior end. This acts like a snorkel, allowing the larva to breathe air while submerged. The siphon is usually about as long again as the maggot's body (20 mm when mature), but can be extended as long as 150 mm. This organ gives the larva its common name. It lives in stagnant, oxygen-deprived water, with a high organic content. It is fairly tolerant of pollution and can live in sewage lagoons and cesspools.
This one was found in a container in our vehicle so really no idea where it came from. It was also a hasty shot as I was on my way out so sorry I did not get a front view. Poor thing seemed desperate to get away anyway. When I found it I had no idea what it was so put it on the wall in the garden which I now realise was the completely wrong place for it. I hope it survives somehow.
"Eristalis tenax", the common drone fly, is a common, migratory, cosmopolitan species of hover fly. It is the most widely distributed syrphid species in the world, and is known from all regions except the Antarctic. It has been introduced into North America and is widely established. It can be found in gardens and fields in Europe and Australia. It has also been found in the Himalayas.