The Meaning of Life, the Universe, and Everything.
A general consensus is that the Outer End is barren: There's only floating islands made out of End Stone, Chorus Fruit, Endermen, and the rare End Cities. Particularly weird is the lack of danger there. So long as you're careful while bridging, and don't look at Endermen in the eyes unless you have a ceiling right on your head, you're perfectly safe. While it's comprehensible that the Outer End's relative safety is intended or order to make it somewhat less horrible to traverse, the end result is simply dull.
While I'm sure this mob alone won't fix the lack of features and the barren landscape of the Outer End, it can fix both the annoyance of moving through the End Islands by bridging them, as well as provide with an alternate means of flight compared to the Elytra; albeit at a cost.
The Ender Floater:
Physical description: Resembles a cross between a small blimp and a fish. It has purple scales, 3 fins on each side, and a hanging tongue resembling a rope. The fins are a lighter shade of purple, the eyes are blue, and it's tail and fin tips are maroon. The borders between scales are white, and overall the scales produce a pattern that resembles Chorus Plants. The tongue is cyan-colored. It's a rather large mob, being about half the size of a Ghast.
Spawn Mechanics: Spawns in large End Islands, and has to spawn close to Chorus Plants in the End.
Behavior: The Ender Floater is a flying mob. It can fly horizontally at almost the same speed as the Player can sprint, but changing altitudes is more difficult for it, which halves it's speed.
Ender Floaters are hostile, and make few noises (You can hear them dropping their tongues, which are generally in their mouths except when they're performing their attack).
They attack by floating on the Player (3-5 blocks), dropping their tongues on the Player (Which sticks the Player to them similarly to a Lead), and retracting until the Player is touching the Floater. At this point, it will start to float upwards, until it reaches an altitude of 12, 20, and 50 blocks above the position the Player was in, depending on difficulty. It's worth noting that, during this ascent, the Player will take damage at a rate of 1 point every 2 seconds.
Stats and drop: The Ender Floater has 32 points of health (Double that of a spider's), and is solely affected by Sharpness and Power. It drops a Gas Bag, similarly to Spiders.
Gas Bag uses:
1: Deployable Balloon:
The Cake is a Gas Bag, and Golden Apples are Phantom Membranes.
Deployable Balloons are tools with 32 uses each. Upon deploying, it extends a small balloon, about the size of a Pig's torso. In spite of the apparently inadequate size, it's capable of slowly lifting the Player upwards at a rate of 4 m/s. Each use works for up to 30 blocks. Combined with Ender Pearls, it can be used to quickly climb cliffs and other surfaces without much preparation. Most valuably, it can save the Player from falling into the End's Void.
2: Large Balloon:
This is a truly interesting item to craft. In order to use it, it has to be placed on ground. By itself, it's useless, but it's possible to attach a Lead to it after using it on a Fence block. Once this is done, right-clicking the Balloon will allow the Player to enter it. Once this is done, pressing the jump button will cause the Balloon to ascend, taking 1 second to start doing so. Once at an appropiate altitude, not doing so every 20 seconds at least will cause the Balloon to start descending. It can carry up to 4 entities. Aesthetically, it resembles a kite balloon, as opposed to a round one.
The balloon's maximum range (Altitude, and how far away it can be) are controlled by the lead's length. While attached to the fence, the Player can steer the balloon freely similarly to a Boat. It's possible to use more Leads in order to extend it's range, up to a maximum of 300 blocks. This is done using an inventory that is accessed similarly to a Horse's.
The inventory has a slot in which the Player can place Leads in order to modify the Balloon's flight range.
Alternatively, it's possible to place a Blast Furnace there, which turns the Balloon into an Airship. If the balloon was already tethered, the Lead will detach and drop.
The Airship requires fuel, and unlocks a Fuel slot, which only accepts Blaze Rods and Lava. Blaze Rods will power the airship for 80 seconds, and a Lava Bucket will work for 1500 seconds, respectively lasting 3/4 and 3/2 times as long as they would in a Furnace.
Controls are done through the mouse. The airship will fly in the direction the Player is looking at, and speed is reduced to 4m/s while climbing. The flight direction is locked if the player presses the Jump button at the same time, and the Airship can accelerate and deccelerate gradually (At a rate of 0,125m/s^2) by pressing W and S, respectively, until it reaches maximum speed. Turning while moving is done gradually, and won't be anywhere near as instant as in, say, a Boat. Generally, Airships fly at the cost of speed, being expensive, and needing fuel. In comparison to Elytra, they're also less agile, but can be made to land vertically.
Other blocks can be placed in the slot instead of a Blast Furnace. For instance, putting a Dispenser will cause it to shoot an item from it's inventory if the fence it's tied to receives a Redstone Signal, a Dropper will make it drop it, and putting a Hopper will cause it to descend and unload it's inventory on a chest within the lead length's radius.