This question deals exclusively with the metaphorical interpretation of the Serpent as Satan/evil inclination/Devil/etc, not as a biological species.
The Serpent was cursed by God with :
"וַיֹּאמֶר ה"א אֶל־הַנָּחָשׁ כִּי עָשִׂיתָ זֹּאת
אָרוּר אַתָּה מִכָּל־הַבְּהֵמָה וּמִכֹּל חַיַּת הַשָּׂדֶה
עַל־גְּחֹנְךָ תֵלֵךְ וְעָפָר תֹּאכַל כָּל־יְמֵי חַיֶּיךָ׃"
"Then God said to the serpent, “Because you did this,
more cursed shall you be than all cattle and all the wild beasts:
On your belly shall you crawl, and dirt shall you eat all the days of your life." Gen 3.14
The commentators I looked at unanimously interpret "נחש" here as a species, completely ignoring the idea of it being a metaphorical evil being .
For the metaphorical נחש, what does the curse mean?