Prophysaon andersoni, common name the reticulate taildropper, is a species of air-breathing land slug, a terrestrial pulmonate gastropod mollusk in the family Arionidae, the roundback slugs.

These slugs are notable for being able to self-amputate (autotomy) a portion of their tail.

The color of the body is a grayish or reddish brown, or can be yellowish.

The dorsum is furrowed with a reticulated pattern like a mesh of diamond shapes.

[3] This species of slug occurs in North America, including California, Oregon and part of Montana.