The end Boar is a new mob that would be found in the end (No Duh Sherlock). It is 3 blocks long and 2 blocks tall; Appears as a larger, skinnier pig with an elongated snout and two drill-like tusks; And it has a primarily black color scheme with Purple highlights and Primal, Red eyes.
It spawns rarely on the central island and uncommonly In the outer Islands. as for behavior, The End Boar is a Voracious Eater. It can frequently be found rooting at the bottoms of chorus plants; it Will attack any mob that isn't an endermen or Shulker; and Will eat anything that could be considered food from off the ground, So Potatoes, Pork chops, Saplings, Anything like that is fair game.
In Combat, The Boar has 30 HP, 70 armor points (same as leather), and deals a bit more damage than a zombie if you get into melee Range. However, It's main method of attack is a charge attack, Where it will spend 1 second charging up before making a beeline towards you. If this attack hits, it will do the same amount of damage, but will apply a HUGE knockback effect, making the risk of falling to your death very real. However, It can't turn while charging, meaning you can sidestep it and attack it as it passes by. Of course, you can't just shoot it from a Distance or box yourself in. This is because The Boar's main gimmick is its ability to "phase out" blocks and projectiles. What this means is that any blocks it would hit while charging (it can charge up 1-block high ledges like horses btw) Will turn semi-transparent and lose all solidity, Allowing it to charge straight through your fortifications and into you. As for projectiles, they'll jsut become non-solid and pass through the end boar. This means you can't "cheese" the boar like you can enderman, But a good player will quickly master the sidestep+swipe pattern, allowing them to defeat it without taking a scratch.
When you defeat the Boar, It will drop 0-2 "Phase Truffles" Which have several uses.
The first use is for an "Obsidian Mirror" This is crafted with 4 Phase truffles in the corners, 4 obsidian on the sides, and 1 eye of ender in the center. To use this block, you must first place one into the world, and then right-click it with another to Link the two. Once linked, you can place the second one down, and you will be able to throw items in one mirror to have them pop out the other, akin to the "Magic Mirror" from the mod Thaumcraft. In addition, if you have a linked mirror in your inventory, you will be able to drag items onto it and press Right-click to send the items through without having to place the mirror. This is useful if you're caving and end up with a full inventory, Just send the extra spoils into a sorting system and keep on mining. Do note that only 2 mirrors can be linked at a time, so you can't have a dozen different mirrors all feeding into one.
The second use for the phase truffles is for a "phasefield". With this block, you can again link two together with the above-mentioned method, and if you place two linked phasefields in the corners of an area, Applying a Redstone signal to one will cause any blocks in the area to phase out, allowing you to pass through them. Just because that was probably confusing, let's have an example. Let's say there's a 5x5 cube of stone I want to phase out. So I place one generator in the corner of the cube, so that the Corner of the field is touching the corner of the cube, Right-click that field with the second phasefield to link them, Then place the second field in the adjacent corner. I can then give one of the sides a Redstone signal and the stone cube will phase out.
The third use for the Truffles is to brew a "potion of phasing". This will make you immune to the pushing and crushing effect of mobs that was added in 1.9. This is useful because it allows you to walk through a dense field of livestock without being pushed around everywhere. This potion doesn't have a level 2, but can be extended with glowstone. The potion can also be inverted with a fermented spider eye to get a "potion of (To be Determined)", This causes you to take increased push force from entities, as you would expect.