The phrase "the snark was a boojum" from Lewis Carroll's "The Hunting of the Snark" suggests that encountering or identifying the snark (a mysterious or elusive creature) is as dangerous or baffling as a boojum, which is a fantastical and potentially perilous entity. It highlights the whimsical yet uncertain nature of the journey undertaken by the characters in the poem, emphasizing the theme of the unknown and the unpredictable.

This line encapsulates the poem's playful tone and its exploration of curiosity, adventure, and the danger of illusions. It implies that some mysteries or discoveries may be more threatening than they appear, and that the pursuit of the snark, like the encounter with a boojum, can lead to unforeseen consequences. Carroll uses fantastical imagery to provoke thought about the limits of understanding and the nature of adventure.