Black worm looking thing?

[randy210]

I recently found a bunch of black worms in my sand I dont have any pics sorry but they are small about 1/4" to 1" very skinny and when I get close to the tank they retract to become very small I dont know what they are does anyone know what im talking about?

[OoNickoC]

common in live sand, species id is probably almost impossible without magnification, if they are what i suspect them to be then theyre a good sign of healthy (or at least living..) LS.