Black and peacock spider works on Ullswater. A local expert told me that a long time ago.
B

 

plus one

 

https://www.fish4flies.co.uk/Dry/Terrestrials/Green-Snail

The original floating snail by Cliff Henry was cork glued onto hook shank then covered with peacock herl. Cut slit in the cork to so it sits on top of the hook then just wind peacock herl over the cork after shaping the cork. You could also use foam. Simple way is as jaybeegee posted.

 

If you have some booby cord the a knot in it, cut one end at a point and tie it on a hook the other, colour the cord with permanent pen and add a dubbed body if you want.

Steve

 

Here's an S-B-S for a foam snail

https://globalflyfisher.com/patterns/foam-snail

 

His flies are just superb. Occasionally try and copy one when I have a decent bit of time on my hands, and it is incredibly rewarding. Like Wingmans flies, they are almost too good to use though.
That looks relatively very easy, and certainly going to knock a few off.
Cheers.
Well found.

 

If you leave out or substitute the lead for dubbing it might make a floating fly.

 

A Goofus Bug would be a reasonable imitation, and easy to tie, easker1

 

Years back a member named Geordie somthin or another from Ireland did a rolled up 2mm foam snail that looked real close to the real thing. Not sure if it's still in the old posts. He pissed off someone and got the red card.