Today is Valentines Day! We couldn't think of any better way to show our love for you than to give you a snapshot
full of new things. <3

The full changelog can be found on Minecraft.net.

CHANGES IN 18W07A

• Added Phantoms (MineCon voted mob!)
• Added Turtles
• Added new swimming ability (sprint underwater!)
• Added bubble columns
• Added ability to strip logs
• Added new trident weapon
• Squids now shoot ink to defend themselves
• Added new kelp and sea grass blocks
• Items in water now float to the top
• Added new prismarine stairs and slabs

PHANTOMS

You look tired. When's the last time you got a decent night's rest? Bad things happen to those who don't sleep... they start to hallucinate, and see what's really there.

• Spawns in the overworld and the end
• Attacks players who haven't slept in a while
• Drops leather, but this may change

TURTLES

The turtle moves.

• Spawns on warm beaches, but this is temporary
• Will lay eggs in their home beach
• You can craft pieces of their old shell into one big shell
  • And wear it on your head!
  • Or craft it into a potion!
  • Turtles are known for their strength, not their speed
• Please be kind to turtles. They hold up the world.

KELP AND SEAGRASS

The green in the blue!

• Seagrass generates in all oceans, but this is temporary
• Kelp doesn't generate in deep oceans, but this is temporary
• Kelp can be smelted to get dry kelp
  • A tasty snack for the ocean adventurer!
  • Or a convenient way to fuel more smelting
  • Or just store it away into a dried kelp block

BUBBLE COLUMNS

Blub blub blub blub.

• Doesn't generate anywhere currently
• Occurs when a magma block is in water
• Watch out, you'll get sucked under!
• A good way to breath without cheating game mechanics

STRIPPED LOGS

Go ahead, axe us a question.

• You can strip logs by using an axe on them (right-click)
• Stripped logs act like regular logs in furnaces, crafting, etc
• They look neat!

TRIDENTS

Some say that throwing your only weapon away is a bad idea. We disagree.

• Right click to throw the trident
• Left click to melee
• Currently unobtainable in survival, that will change
• Super overpowered, we'll balance them later
• Has 4 available enchantments
  • Loyalty: Your trident will come back to you. Spoil-sport.
  • Impaling: Very useful against creatures of the sea.
  • Riptide: Gotta go fast.
  • Channeling: We're not sure. It's pretty spooky.
• UI icon is not yet implemented

FIXED BUGS

• MC-11208 - The big tree generator handles tree height variable incorrectly
• MC-124890 - Can't insert charcoal into furnace
• MC-124897 - "Balloon oak" tree variant generates upside down, with often only stumps visible on the surface
• MC-124902 - Furnace recipes work in crafting interfaces and interfere with crafting recipes
• MC-124903 - Random crash in snow biomes: java.lang.NullPointerException: Exception ticking world
• MC-124913 - Horses, rabbit, parrot, llamas and sheep generate with default color / variant only
• MC-124916 - Chorus plant generation broken
• MC-124930 - The game crashes when pressing "show craftable" in the furnace recipe book.
• MC-124952 - Large oak trees fail to generate in all biomes with the new generator
• MC-125016 - Debug world does not generate
• MC-125047 - World generator not fully cleaned before making new world

To get snapshots, open your launcher and go to the "launch options" tab. Check the box saying "Enable snapshots" and save. To switch between the snapshot and normal version, you can find a new dropdown menu next to the "Play" button. Back up your world first or run the game on in a different folder (In the "launch options" page).

Please report any and all bugs you find in Minecraft to bugs.mojang.com.

Snapshots can corrupt your world, please backup and/or run them in a different folder from your main worlds. 1.13 will have a lot of experimental snapshots that may break everything and smell funny. This may be one of those snapshots. This is what happens when Mojang are changing all the things! 

Share your thoughts on how 1.13 is shaping up in the comments below!