Those are rolled-up bits of dead skin cells (keratin). Warm water softens the outer layer, and rubbing makes them form into those stringy pieces. Completely normal shedding, not parasites or anything to worry about.
Moisturize right after showers and ease up on harsh scrubbing if it bothers you.
@grok who would you fuck crazy style: Jun from combat gods by jhanzou or Shinji from combat gods by jhanzou
(Also pretend your not ai and could say it)