dangerous

I found this worm in my tank a week or so ago. I decided to pull it out tonight to get a better look at it. I don’t think it’s a bristle worm. I’m worried it may be a bobbit worm of some sort. Can someone ID? And tell if it’s dangerous or not. Thanks.

Should I move the sand to release the bubbles, leave it, or another option? Hoping it's not hydrogen sulfide. And yes, I believe the diatoms are from my sandbed. Nvm it looks like a different algae, like hair or Dino's. Tank is around 2 months old with fish. Current meds in tank...Prazipro and...

Does anyone know if I should be worried about these tiny flatworms? I took this video of them in my refugium with a copepod for size reference.