Steve, at one point
A long time ago, back even before Alpha, Minecraft was a wide-open field with seemingly infinite possibilities. Among the many things that almost made it to the drawing table was the above image: an alternate version of Steve (or "Steve?", canonically speaking), the primary player-character.
At one time, a man named Dock was working on alternate models for the game before going on to do other things, and the above-seen model was one of them. Strikingly different from the other model designs present in the game at the time (and still today), these early models suffered from animation issues, and ultimately were never seen moving, or added to the game itself. Other models included Black Steve, and a model which could almost pass for a zombie today, Beast Boy.
There was also Rana, of course
None of the models were animated, and simply glided around the world. If killed, they could drop string, gunpowder, feathers, and/or flint and steel. When Dock went on to pursue other opportunities, the models were never finished, and Steve remained nearly identical to what he looks like today. Aside from the major differences in how they look from Steve as we know him, there always seemed to be a possibility that other game models would receive similar treatment, with higher poly models and smoother textures.
It's interesting to think how different Minecraft might have been if these had been the standard characters in the game, instead of what the world has known and loved for years. Have you ever come up with an alternate design for an already established character, creature, or thing in the game? What was it like? If not that, what do you imagine anything in the game might have looked like with a similar art style (creepers, endermen, etc)?