The term 'boojum' is derived from Lewis Carroll's poem 'The Hunting of the Snark'. The poem follows a group of adventurers on their quest to find a mythical creature called the Snark. The boojum is a particularly dangerous type of Snark, and is described as being 'softly and suddenly vanishing away'. In the poem, the boojum is the last creature the adventurers encounter, and it causes them to disappear.