Questions - Need some input

Are these guys what I think they are?

Red flat worms?

Noticed these on my glass the other night. Can really only see them when you look up at an angle towards the lights. They look like smeared finger prints. I also think maybe they be from the snails slime while they are hanging out on the glass. I've tried scrubbing, rubbing, and scrapping but nothing really works.

Anyone have any idea what might these be from and how I could get them off?