Heffalump

The sole appearance of heffalumps in the books is imagined, 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.In the third chapter of The House at Pooh Corner, Pooh and Piglet fall into a similar trap (it is implied it was the same trap) and think that it was made by a Heffalump to catch them.

[2] Shepard's illustrations in Milne's books depict heffalumps (in Piglet's dreams) as looking much like elephants.

[1] In Disney's adaptations of the stories, Heffalumps are first mentioned in the 1968 featurette Winnie the Pooh and the Blustery Day and later The Many Adventures of Winnie the Pooh, and seem to be a product of Tigger's imagination.

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, with rabbit-like tails and stitches as would be found on a stuffed animal.

Piglet befriended a young heffalump named Junior in two episodes of The New Adventures of Winnie the Pooh.

There are several Winnie the Pooh video games where the Heffalumps are an antagonist to the storyline of various levels in Piglet's Big Game and Winnie the Pooh’s Rumbly Tumbly Adventure.