I am not sure what the animators were thinking (or taking) when they created the heffalump and woozle scene in Winnie the Pooh and the Blustery Day. It was very Fantasia-esk and a little - odd. In the 1960s there was some Pooh merchandise which had heffalumps and woozles but it wasn't until 2005 when Disney released Pooh's Heffalump Movie that we met Lumpy and the heffalumps were mainstream again. Both Pooh's Heffalump Movie and the sequel Pooh's Heffalump Halloween were much less dream-like.
1960s merchandise is very rare and always a great find. Recently I found a vintage Heffalump and Woozle in fantastic condition. The hang-tag on the Woozle is from pre- bardcode days and also in great condition. (Don't ask what I paid for them... or if you do -- make sure you're sitting...)
If you're unfamiliar with the "unique" song and scene -- click here to listen to the Heffalump and Woozle Song by Robert and Richard Sherman.