Time for lore nitpicking. This art seems to show Vraska as a snake, but the Bloomburrow web story implied she turns into a lizard on Bloomburrow. Or maybe people don't always transform into the same thing each time.
It should be a lizard, because snakes are mammal eating predators and thus count as Calamity Beasts rather than the fully sapient and civilised lizards.
Guess the art description was sent before everything was finalised... Or someone was overworked and overlooked it.