Hostile Mobs- Zombies

I stayed up until 3am just to watch the Minecon Day 1 youtube livestream, specifically David, Steven & Jordan's talk session on Minecraft animations. And I'm proud to say that I didn't regret doing so. It was a wonderful experience. Now on to the first hostile mob!
 
First, a quick question: why is this week's mobs (monsters) labelled 'hostile'?

It's simply because these mobs will attack you and try to kill you if you aren't prepared for them.
 
Thus, today's featured hostile mob is none other than... you probably guessed it, the Zombie! Here's a short video by MCSpotlights to get us started:

 

Definition
 
Zombies are the most common of all hostile mobs in Minecraft. They are undead mobs with 10 health points and spawn in dark places like caves.

They are easily identified by their dark-green skin, cyan shirt and darker blue pants. You will also be able to hear groaning and growling noises if you're nearby.
 
There are three kinds of zombies in the regular game:
 

[from left to right: normal, baby, villager]

 
Normal zombies: are 2 blocks high. They move as fast as the player's walking speed.
 
Baby zombies: are about 1.1 blocks high and are extremely fast. However, they cannot fit through one block gaps.

Villager zombies: are similar to normal zombies, except for their heads. They either spawn naturally or were originally villagers attacked by zombies.
 

[zombies trying to attack villager]

 
Also, zombies tend to attack villagers within a distance of 16 blocks. Being an undead mob, they burn in sunlight/during daytime except for armoured zombies and baby zombies.
 

[zombie burning in sunlight]

 

[armoured zombie not burning in sunlight]

In addition to all that, Minecraft 1.5 update causes more zombies to spawn if you attack one directly. So approach them with caution!

(Item) Drops

Zombies drop a whole variety of items when they are killed, the most common being rotten flesh. Other rare drops include carrots, potatoes, iron ingots, tools like shovels and even armour.
 

[some examples of zombie drops]

 
Note: Only armoured-zombies have a chance of dropping armour. These zombies are tougher to defeat due to the extra protection, but a good sword should take them down quickly.

Personal experience

I remember my first time playing the mobile version of Minecraft. I certainly wasn't prepared when night came, so all I did was dig a hole and hide in it. The next thing I knew I was attacked and killed by a swarm of zombies. It wasn't very fun, and I spent the next of my days in a dirt house on a tree on top of a hill.

That's it for zombies. I hope this helped somewhat.

Peace out! :)