A Heffalump is a type of fictional elephant in the Winnie the Pooh stories by A. A. Milne. Heffalumps are mentioned, but never appear, in Winnie-the-Pooh (1926) and The House at Pooh Corner (1928) and later featured in the animated The New Adventures of Winnie the Pooh (1988–1991) and Pooh's Heffalump Movie (2005). Physically, they resemble elephants; Shepard's illustration shows an Indian Elephant.
In the fifth chapter of Winnie-the-Pooh, Pooh and Piglet attempt bravely to capture a heffalump in a trap. However, no heffalumps are ever caught in their trap, and indeed they never meet a heffalump in the course of the books. The sole actual appearance of heffalumps in the books come as Pooh tries to put himself to sleep: "[H]e tried counting Heffalumps [but] every Heffalump that he counted was making straight for a pot of Pooh's honey ... [and] when the five hundred and eighty-seventh Heffalump was licking its jaws, and saying to itself, 'Very good honey this, I don't know when I've tasted better', Pooh could bear it no longer." We learn nothing more about the nature of the beasts in the writings, unless by "nature" we refer to the "nature" of absences.
In the third chapter of The House at Pooh Corner, Pooh and Piglet fall into a similar trap (it's implied it was the same one) and think that it was made by a Heffalump to catch them. Pooh and Piglet rehearse the conversation they'll have when the Heffalump comes, but Pooh falls asleep and when Piglet hears a voice, he panics and says the wrong thing. He is mortified when the voice turns out to be that of Christopher Robin. Heffalumps are purple, have long trunks, and, fuzzie tails.
Although this is never explicitly stated, it is generally thought that heffalumps are elephants from a child's viewpoint (the word "heffalump" being a child's attempt at pronouncing "elephant"): E. H. Shepard's illustrations in A. A. Milne's original books depict heffalumps (as seen in Piglet's dreams) as looking very much like elephants.
In Disney's adaptations of the stories, Heffalumps are first mentioned in the 1968 featurette Winnie the Pooh and the Blustery Day, and seem to be a product of Tigger's imagination. Heffalumps first actual appearance was in the television series The New Adventures of Winnie the Pooh. In both the animated films and all subsequent television series, they are also depicted as looking like elephants, albeit slightly cuddlier and less fierce than those Pooh imagines in the books and with rabbit-like tails.
In the animated television series, most heffalumps are enemies of Pooh and his friends. They are known to steal honey and are often associated with woozles. One particular heffalump named Heff was the dim-witted sidekick of Stan the Woozle and was afraid of Roo because he thought Roo was a giant mouse. (This is perhaps a reference to the Looney Tunes running gag of Sylvester mistaking Hippety Hopper for a giant mouse and the fear of mice inherent in elephants.)
Piglet also befriended a young heffalump named Junior in two episodes of The New Adventures of Winnie the Pooh. Junior lived with his parents, and his father, Papa Heffalump, was voiced by Jim Cummings. Mama Heffalump often had to remind Papa Heffalump of his many allergies. They appeared in a song called "Heffalumps and Woozles" with their partners, the woozles, in the film The Many Adventures of Winnie the Pooh. Here, Tigger described them as honey-eating monsters. They and the song are also featured in the attraction at Walt Disney World, also called The Many Adventures of Winnie the Pooh, where the riders travel through the heffalumps and woozles in Pooh's dream.
Cultural impact 
Since the 1950s heffalumps have gained substantial fame outside the Pooh stories.
- The term "heffalump" is whimsically used by adults to describe an elephant, or a child's view of an elephant.
- The term "heffalump trap" has been used in political journalism for a trap that is set up to catch an opponent but ends up trapping the person who set the trap (as happens to Winnie the Pooh in The House at Pooh Corner).
- The protagonist (Gnossos Pappadopoulis) in Richard Fariña's 1966 novel Been Down So Long It Looks Like Up to Me believes his best friend to be named Heffalump for the majority of the novel, although Gnossos discovers in Cuba that Heffalump's birth name was Abraham Jackson White.
- There is a musical score called To Catch a Heffalump (1971) by Willem Frederik Bon.
- Expressen's Heffalump is an annual literary prize awarded to year's best Swedish author for children and young adults.
- A search for "heffalon" particles is the subject of an April Fool's day paper posted on a scientific pre-print server.
Pooh's Heffalump Movie, released in 2005, looks at the differences between the denizens of the Hundred Acre Wood, and the Heffalumps, whom they fear as predators, cleared up after Roo becomes friends with a Heffalump named Lumpy. A sequel to this movie called Pooh's Heffalump Halloween, was later released.
Lumpy the Heffalump later appears in the television program, My Friends Tigger & Pooh, on the Disney Channel. He continues to appear as Roo's friend and joins the gang on many adventures.