I met a Slug the other day.
His name suits his appearance just fine.
This shell-less terrestrial, gastropod mollusc it was.
The word “slug” is a part of the one that has no shell.
Sometimes it’s a very reduced shell, or has only a small internal shell.
Rather a slimy slithered creature.
Greatly contrast to the common snail, applying to those with a coiled shell.
But large enough to retract its soft parts fully into it.