Terraria (Wiki): Light Disc

The Light Disc is a type of thrown melee weapon that returns to the player after damaging an enemy (non-piercing), traveling for 34 tiles away, ricocheting for two consecutive times, or hitting a solid object. The Light Disc can spawn up to six projectiles and is capable of autofire.

In desktop, mobile, console, the Light Disc cannot be stacked but can still be quickly fired. In 3DS, old-gen consoles, up to five projectiles can be stacked in a slot, allowing all Light Discs to be thrown at the same time.

When normally used, the Light Disc will leave a blue trail effect and emit light, making the players see better in the dark. It also phases through any type of block when returning to the user. The Light Disc can also squeeze through one-block-wide gaps at the right range. When used on liquids, the Light Disc’s travel speed and range drastically decrease.

It is a general rule to aim above enemies for unlimited piercing when using the Light Disc. This unique property is possible thanks to all Boomerang’s capability of phasing through walls. One can easily handle a wave of strong enemies and deal high knockback with the Light Disc.

At the right range, enemies will receive two consecutive damage as the Light Disc goes to the target and back to the player. Damaging enemies on both ends of a wall is also possible when executed at the right position and range. This unique property makes the Light Disc pass through walls unhinged while keeping hostiles at bay.

Since the Light Disc is a melee weapon, some accessories, all flasks, and armor can enhance its travel range, flight speed, and apply flask-related buffs.

During boss encounters, especially against the Twins, the Light Disc is the perfect weapon since they mirror the player’s movement behavior. Although it lacks a piercing capability, a bouncing Light Disc can squeeze through a 1-block wide wall behind - ideal against sneaky hostiles.

The Light Disc is generally a good option for clearing waves of enemies because of its autofire and multiple projectiles fired. However, the thrown weapon is also excellent at eradicating hostiles in tight areas, like the Underground or Mushroom biome.

The Light Disc is best modified with Godly or Demonic, providing a wide array of stats improvement (desktop, mobile, console). The same cannot be done in 3DS, old-gen consoles.