A bandersnatch is a fictional creature in Lewis Carroll's 1871 novel Through the Looking-Glass and his 1874 poem The Hunting of the Snark.

Carroll's first mention of a Bandersnatch, in the poem "Jabberwocky" (which appears in Through the Looking-Glass), is very brief: the narrator of the poem admonishes his son to "shun / The frumious Bandersnatch", the name describing the creature's fuming and furious character.

But while he was seeking with thimbles and care, A Bandersnatch swiftly drew nigh And grabbed at the Banker, who shrieked in despair, For he knew it was useless to fly.

Without rest or pause — while those frumious jaws Went savagely snapping around — He skipped and he hopped, and he floundered and flopped, Till fainting he fell to the ground.

The Bandersnatch fled as the others appeared Led on by that fear-stricken yell: And the Bellman remarked "It is just as I feared!"