Rat Tailed Worm

On our patio, I was dealing with a flooded wine barrel top. The rain collects and sits there. There is no drainage (was no drainage until my drill got to work), but the 3 cm of water was collecting leaves and starting to become stagnant.  Not pretty.
The water started to drain out of the hole I drilled to let it flow out of the top without compromising the integrity of the actual barrel itself.  It worked.  But, as the level dropped, I saw several of these odd-looking worms wriggling in the water.  Not having seen anything like that before, I did what most people do - looked up “water born worm with long thin tail” on Wikipedia.
It turns out they are called Rat-Tailed Worms.  In fact, they are not worms at all, but the larvae of Hover Flies!  The long tail allows them to live in stagnant, low oxygen levels of water, by breathing through the end of it!
Who knew!