Traps

Traps are placed items that cause harm to players and enemies. Most are mechanisms that are naturally generated underground and below. When found initially, they are wired to triggers, such as Pressure Plates, intended to harm players who inadvertently activate them. Traps can be collected by players and utilized in arenas, and are usually essential to battling events like the Pumpkin Moon and Frost Moon.

The Spike and Wooden Spike are exceptions, as they are not mechanisms, but static placed items that simply cause damage on contact. The Land Mine is a trap-like item, though never generates naturally, and is instead purchasable during Hardmode.

All traps, including their triggers, are illuminated by the Dangersense buff, allowing the player to avoid and collect them. Their wiring can also be seen if the player holds a mechanism-related item in their hand, for instance a pressure plate. The player can also see wires even in darkness if they have a or  in their inventory

Reusable Traps
Reusable traps generally fire sharp projectiles. They can be activated infinitely with a few seconds delay.

These traps consist of spawn statues, such as skeleton statues, wired to a red or green pressure plate. A monster spawns if a player steps on it and if the plate is in the enemy's way, each monster may spawn a new one, resulting in swarms of enemies, spawning until the spawn limit is reached.

Dart Traps fire a poisoned dart which resembles a Wooden Arrow when activated. When found naturally, they are always wired to Pressure Plates in their line of sight. The Pressure Plate can sometimes be very far away from the Dart Trap.

Dart Traps are the most commonly encountered trap, found throughout the Underground and Cavern layers, being the only variety not found in the Jungle Temple. Many can also be found in the Dungeon.

Super Dart Traps function like ordinary Dart Traps, but do almost double the damage. They shoot what appears to resemble a Poison Dart, as opposed to an arrow. They are found in the Jungle Temple only, and are the second most common trap in there.

Spiky Ball Traps drop a single spiky ball that bounces and persists for a long time before despawning. The projectile's prolonged lifetime allows it to do significant damage to anything in its path, which comes in handy for terrain often traversed by enemies. Spiky Ball Traps are found in the Jungle Temple only, and are the most common of the traps in there.

Spear Traps deploy a long spear down from the block, which can reach surprisingly far lengths if not obstructed. They have a shorter activation period than other traps. They are found in the Jungle Temple only, and are the second most rare trap in there (Only succeeded by Flame Traps).

Flame Traps fire flames, similar to those of the Flamethrower, that extend 23 blocks with 1 block above and below, and inflict the On Fire! debuff. They are found in the Jungle Temple only, and are the most rare of the traps in there. Often, they don't even spawn in a world at all.

Geysers act like vertical Flame Traps, throwing fire that pushes up the player when touched. These do not inflict the On Fire! debuff. The fire they emit can pass through several blocks and still hit the player. They are found deep underground, usually near lava sources.

Spikes and Wooden Spikes are not mechanisms, instead dealing damage on contact with a player. They are found commonly in the Dungeon and Jungle Temple, respectively.

Single-use
Single-use traps can only be used once, and require player intervention to reset. They can be found in the Cavern and Underground.

Boulder traps features a Pressure Plate wired to a 2x3 arrangement of Active Stone Blocks above it, with a Boulder resting on top. When the Plate is triggered, the stone blocks become inactive and the Boulder drops on the area below. They are dangerous in dark areas as players won't be able to see the boulder or pressure plate. They affect all entities, so when used properly can be used to defeat enemies and bosses.

Explosive traps come in two varieties, but are based around the same means of killing the player. The more common variant, found only on the Desktop version and Console version, is a Detonator wired to a nearby Explosives block, usually sitting atop a large ore vein. The rarer variant/only variant on the Mobile version is a less visible Pressure Plate, usually buried nearby. In either case, the triggering device sits within the explosive radius of the block, causing the player to be caught in the explosion though it is possible to activate the Detonator without being caught in the blast radius. There is no forewarning to this explosion, and Explosives deal upwards of 500 damage to entities caught in the blast, making undiscovered Explosives Traps extremely dangerous well into Hardmode. It is also possible to find dummy variations of this trap, where the detonator or pressure plate and large ore vein are present, but not the explosives, or the triggering mechanism is not properly wired to the explosives.

The Land Mine is a placed Hardmode item that explodes on contact with a character, or when activated via wire. These do not generate naturally, and are rather purchased by the Demolitionist, and placed by a player.

These grow naturally in the Corruption, Crimson and Underground Jungle respectively. Touching them will damage the player and destroy the block.

Upon its destruction, it will fall to the ground and release Bees that will attack the closest player.

Tips

 * Trap wiring displays on screen, meaning the player can hold an item like a Pressure Plate to see wires underground that might be connected to darts or boulders.
 * Randomly generated traps are a very cost-effective method of acquiring Wire once you have a Wire Cutter, saving you for every bit of wire collected (as opposed to purchasing Wire from the Mechanic).
 * When placed effectively, Traps can be useful in events.
 * When multiple traps are naturally generated close to each other, their wiring may intersect. This leads to multiple traps with multiple triggers.
 * Most traps deal double the damage to players In expert mode.(In addition to the double damage players normally take from traps).
 * The explosive trap's veins are usually bigger than an average vein and can have rare ores in them, so disarming the bomb and mining the ore can prove useful.

History
Falle Piège