Goblin Army

The Goblin Army (also known as the Goblin Invasion and the Goblin Siege) is an Event when unique Goblin enemies spawn in waves. A Goblin invasion has a random chance of occurring at any particular dawn, if the criteria stated below are met. It can also be triggered manually using a Goblin Battle Standard.it can also be spawned right after an attack from the twins.

Criteria
The criteria for a Goblin Invasion to occur at all is as follows:
 * It must be daytime.
 * At least one Shadow Orb or Crimson Heart must have been smashed.
 * At least one player must have 200 HP or more.
 * There must be no Goblin Invasion in progress.

If the player has not met these requirements, they will be unable to use a Goblin Battle Standard to manually summon the event, unless the world is Expert Mode.(On Expert you can summon the event without smashing an orb or heart as long as you meet the HP requirement)

Chances

 * After the spawn criteria have been met, there will be a 1/3 chance every day for the army to first invade.
 * Further invasions (after the first has been defeated) have a 1/30 chance of occurring each day before Hardmode begins, and 1/60 chance afterwards.
 * You will see a random invasion about every 12 hours of playing in normal mode and every 24 hours of playing in Hardmode.
 * The Goblin invasion takes a higher priority than the Pirate Invasion, which can only occur when the Goblin invasion fails to do so.

Initial event


When a Goblin invasion is coming, a message will appear reading: "A Goblin Army is approaching from the [east/west]!"

This message repeats a few times (One time on a small- or medium-sized world and twice on a large-sized world). The direction specified in this message only pertains to the initial wave of Goblins, which spawns at the World's edge and travels to the player's original spawn point. Additional waves spawn immediately within the player's original spawn area when the player is in that area.

If the message says "West", the initial Goblins will come from the left. If the message says "East", they'll arrive from the right. Note that these directions are not related to the apparent motion of the Sun and the Moon, which, in Terraria, appear to move from left ("west") to right ("east").

When the Goblin Army is about to begin spawning around the player's spawn point, the following message appears: A Goblin Army has arrived! and the theme music will switch to the soundtrack "Goblin Invasion."

Completing the event
The event is completed when the player(s) defeat all goblins in the army.

The size of the army is based on the count and health of the players currently in the world. There will be 80 base Goblins, plus an additional 40 for each player that has a maximum health of 200 or more. In single player, the army will consist of 120 goblins, while in an 8-player game, with each player having 200 HP or more, it will spawn 400 Goblins. With the maximum of 255 players above 200 health, the maximum number of goblins in an invasion is 10,280.

When the final wave of Goblins is on the screen, a message will appear saying A Goblin Army has been defeated!, and the theme music will return to normal after the last goblin is killed.

Other Goblins

 * Goblin Scout: An enemy Goblin that drops Tattered Cloth and spawns near the edges of the world. Tattered cloth can be collected and used to craft a Goblin Battle Standard, which is used to cause the invasion manually.
 * Goblin Tinkerer: A Town NPC. Appears bound on the cavern layer randomly after one goblin invasion has been defeated.

Tips

 * Piercing items like Spears and Flails can take out many goblins at once.
 * The Spiky Balls dropped during the invasion are effective in fighting off further Goblins, as the majority of them follow the basic Fighter AI and will mindlessly walk through them.