Shades

Here is my post about a Shade mob:

• Appearance: Looks like a 2-block tall black ghost with frayed robes and red eyes. It floats about .5 blocks above the ground.
• Stats: Has a lifeforce of 20 hearts and deals 3 hearts in damage.
• Special Powers: Can regenerate its health if wounded, can turn invisible at will for up to 5 seconds, can float through blocks like a Vex, and inflicts a random debuff if hit.
• Intelligence: If mortally wounded, it will go invisible and flee, and mostly attacks mobs and players that are at low health. Can sense players from 50 blocks away and will not attack undead mobs.
• Spawn points: Spawns in caves in the Overworld, in the Nether, and floats around the Void in the End.