What are these little strange worm-like bugs in my watering can?

Question

I keep a watering can in the house for my houseplants, and I just looked inside of it after watering one of my plants and there are these little black squirmy worm/centipede-like bugs. I've never seen anything like them before... I also don't understand how they could live in the watering can because I have chemical fertilizer in the water... Does anyone have the slightest idea what these could be, and how they grew in water with chemicals in it?

Answer 1

 im not sure what i once found was a bug or even larvae. if i could submit a drawing of it maybe it would help my description. but i was living in a dampish shed at the computer table i had an itch on my arm and i quickly scratched it in one swoop. i felt a (pardon the eww) booger type substance and when i looked for what it was on the desk i found a slightly translucent almot an inch and a half long width of the led in a hb pencil type worm althoe it had these tiny little scab like feet at its centre and its head was the same color as it body with a slightly larger bulb for what i considerd its head to be. what was strange about its head was it had a smaller half ring going around the top of the bulb to the other side of its head. it was fairly stiff by the time i picked it up. i wasnt even entirely sure it was a living thing so i placed it under the lamp and forgot about it whilst chatting on the net. im really anoyed about this becuase i have never seen a more percular thing. i think it was feeding off me..???