Mojang want to release smaller updates more frequently for Minecraft, instead of one major update each summer. This evening's Minecraft Live stream detailed the Bravery And Bundles update, coming next, but also another update to follow in the next few months.
A creepy update. It doesn't have a name yet, but it'll add The Pale Garden, a new biome of eerie, grey trees and hanging moss that's quiet during the day, but which at night is inhabited by a new mob, the Creaking.
The Creaking are tree-like mobs that blend into their new biome home, making them easy to miss among the trees. If you do spot them and attack them, they don't take any damage.
Instead, a ray of embers will point you towards a block in the canopy of trees, called the Creaking Heart. The heart is puppeteering the Creaking, and it's this you must destroy in order to defeat them.
The problem is that the Creaking themselves move towards you whenever you look away. If you chop down the trees in the Pale Garden, you'll get a new pale wood set you can use for crafting, and the new hanging moss can likewise be transferred or used for a creeping carpet.