Prophysaon, common name taildropper slugs, is a genus of air-breathing land slugs, terrestrial pulmonate gastropod mollusks in the family Ariolimacidae.

[2] These slugs can self-amputate (autotomy) a portion of their tail.

[3] This autotomy has been observed in the species Prophysaon andersoni.

[4] This genus of slugs occurs in North America, including California and Oregon.

Species in the genus Prophysaon include 10 species (9 according to Turgeon et al. 1998[5][6] plus one known undescribed species[3]):