Please help me to identify this red worm I found bunch of red worms coming out of sink. It is rather unusual to find an overwhelmingly large number of worms. It doesn't seem like earthworm or horsehair worm. I don't know much about the worms though. Could anyone please identify it for me.? Notable features are 1. Dark red in color. 2. Has a hook like structure at its rear end. 3. Moves in both directions front and rear. 4. It shrinks when it dwells in water. !enter image description here

Judging from the photo, it's an earthworm, some species of Lumbricidae. If the accident happened in India, this faunistic paper can be of some help.