My first wiggly worm

[Rick's Reviews]

I purchased a new mushroom and whilst taking photos today, I seen this appear. I caught on video
Unfortunately it's under blues and I could not see any colour.I armed myself with turkey baster to suck it up knocking my frags all over the place but he escaped into my sandbed

Any ideas from my poor video and photos,
it has a wierd tail feature (if that helps)

 

[blaxsun]

I don't think it's a tiny bristleworm (hard to make out).