Not certain exactly what these are

[WindeyD]

I have these creatures coming out of my sand from time to time, and frequently find these small cylinders on the sandbed in the morning. I'm Quite certain they are harmless but am curious as to exactly what they are. I'm guessing some variety of worm. Anyone able to ID?

 

[gacolt]

the second pics looks like poop

 

[tyler1503]

+1. Tube worms and poop