Zombie

(Taken From Original Terraria Wiki)

The Zombie is a common enemy that spawns during the night on the surface or when the player is in the jungle at night or underground. Zombies attack by walking into the player and jumping when they need to get past something. During the night, Zombies will come to the player's home and try to break open any Wooden Door available, although they are only able to during a Blood Moon. They can be a serious threat to new players, which makes it a good idea to build a home before the first night. They are an easy enemy to kill when they are alone, but they usually appear in large groups, making them a challenge to new players.

Note: Placing a trench in front of a door will stop zombies from knocking it down, as they cannot jump and knock at the same time.

Zombie Types
As of the 1.2 update, different varieties of zombie can spawn that drop different items as well as change their physical abilities.

Large Zombie
These zombies have a larger body than other zombies. They also have increased health, and a higher resistance to knockback.

Small Zombie
These zombies are much smaller than the usual type of zombie and have increased walking speed, but are knocked back more easily.

Tough Zombie
These zombies are usually larger than others but can still spawn at the same height as regular zombies.They are much like the large variant of zombie but appear to have arrows protruding from their chest. When killed they will drop 4-6 arrows.

Gel Zombie
These zombies come in different variants like the normal zombies do, the only difference is that a gel zombie appears to have a blue slime stuck on its head and when killed drops 2 gel much like a normal Slime does. It serves as a nighttime Gel source, since Slimes only spawn in the Daytime.

Rain Zombie
These zombies cannot vary in size, apperance, or abilities and wear a yellow Rain Hat and Rain Coat. When killed they have a slight chance to drop a Rain Hat or Rain Coat. These zombies can only spawn when it is Raining.

Skull Zombie & Female Zombie
These female and skull zombies have no changes aside from their apperances. Both of these variants do not have any special abilities or drops and can vary in size like other zombies.

Spore Zombie (Mushroom)
These zombies are the strongest zombie in the game. They spawn in Surface Glowing Mushroom Biomes and come in 2 forms. The first form is a fast zombie with spores around its body, and has 180 Health. The other form is a zombie with a Mushroom cap, and is more resistant to knockback, Has more defense and is slower, with 220 health. These Zombies can also spawn at any time.

Halloween Zombie
These spawn only during the Halloween event. They appear wearing various costumes, such as superhero, nurse and hornet among others) and are stronger than regular zombies, having more HP, strength and knockback resistance.