Rashi #1: It is a snail.

Rashi #2: It is like "Shiboles Mayim" (69:16, i.e. a river current). The Lamed is doubled, just like "Yimal Ketziro" (Iyov 18:16) becomes "Yemolel" (90:6).

Rashi: It is melting (it melts more and more); it is a noun. The Tov is a part of the root ¹ that is omitted sometimes. Radak - the root is Masas. This is like "Tevel Asu" (Vayikra 20:12), from the root Balal.

Malbim: If one barely touches it, it emits much liquid; it seems that it melts. The liquid helps it to move easily - "Temes Yahaloch."

Rashi #1 (from Mo'ed Katan 6b): It is a Nefel (stillborn baby) and "Tinshames" (Vayikra 11:30), which is blind (a mole); the Targum is Ashusa. It is like Nefel v'Eshes. The prefix Vov is omitted, like "va'Ani k'Keves Aluf" (Yirmeyah 1:19) is like v'Aluf ¹ .

Rashi #2: It is a woman's Nefel, like "Ishos ha'Zimah" (Yechezkel 23:44). There is a Sov at the end of Eshes even though it is not Samuch, like "Ateres Tiferes Temageneka" (Mishlei 4:9). The Nefel never saw the sun.

Malbim #1: It is a Nefel of a mole.

Malbim #2: It is a blind snake. When one touches it, it becomes hard like a rock and falls to pieces; therefore it is called Nefel, or it melts like water when one touches it. This is a metaphor for David's dispute when the cut the corner of Sha'ul's garment. [One who does not see that David does not seek to kill Sha'ul,] either he is blind, or [his heart] is hard like a rock, and if he does not slacken [from pursuing David,] he will fall into pieces.

Rashi #1: The Nefel ¹ [and according to his first Perush the mole]. Radak - and the snail, which is in its shell].

Malbim: A Nefel of a mole.