Thank you for writing to Ask-Extension with your question about your Hosta plants.  The pictures are very helpful.  Thank you!

The pictures you provided indicate that there is slug activity.  Slugs produce slime and use it to move. A dried slime trail indicates slugs are active in your garden.

Slugs can be described as snails without shells. They are a type of mollusk, related to clams and oysters. Slugs are slimy and soft-bodied, without any legs.  They are generally brownish or grayish, their head contains two pairs of feelers.  A larger pair above carries the eyes and a lower pair below is used for smelling and they can range in size from 1/4 inch to two inches or longer.

https://extension.umn.edu/yard-and-garden-insects/slugs#check-for-slugs-and-damage-in-your-garden-298060

Slugs and Snails

Slugs and snails are major pests of Hostas that can cause large, irregular, unsightly holes on the foliage (Figure 1). Slime trails are also a dead giveaway that these mollusks are eating your Hostas. Since slugs and snails need a moist environment to survive, they usually hide during the day and feed at night.

Control:

Use baited traps in the early spring and after rainfalls during the rest of the growing season.

Thin leaves of crowded Hosta plants to increase air movement.  This helps the dew and raindrops on the remaining leaves dry out faster and makes them less attractive to slugs and snails.

Scatter a light layer of sand (especially course sand) around your plants because slugs and snails don't like to cross dry, course textures.

Mow regularly and remove debris near your Hosta plants to remove hiding places to keep these pests off your Hostas.  

https://www.canr.msu.edu/resources/hosta-pests-and-diseases#msu

Ideas for traps.

Use shallow containers filled with beer as a method of baiting.  Apparently the yeast is what attracts them, and a simple mixture of any yeast and water will also work. 

Diatomaceous Earth -- Apply an inch-wide band of DE around plants needing protection.  When slugs and snails crawl over the dust, it adheres to their bodies, causing desiccation (drying out) 

See the reference below for more information.

https://extension.umd.edu/resource/slugs-and-snails-flowers/

I hope this helps you with your beautiful Hostas.  I looks like the activity is light right now so if you take the above tips you can prevent further damage. 

Please write back if you have any additional questions or need further clarification.  

Thanks again!