Weird item at the bottom of the items section

I was playing Minecraft beta and was going to build a house when I found this weird thing at the bottom of the item section. I have no addons or mods on and through the versions of beta caves and cliffs this item has changed appearance. for a few releases, it looked like a pink stick and plank texture squashed together. but now it looks like a strider fin from the old nether update betas. Mojang please fix I have a video and a few pics. (sorry for the clideo.com watermark I compressed the video and this is the only way)