Magma pebbles served as inorganic projectile weapons, wielded by the sentient Yuuzhan Vong species during their invasion of the galaxy throughout the Yuuzhan Vong War. These pebbles, composed of a shell encasing a magma globule roughly the size of a thumbnail, were primarily employed to neutralize battle droids encountered by Yuuzhan Vong warriors in combat, given the magma's capacity to inflict substantial damage to the droids' circuits and armor.
Unlike most weaponry utilized by the sentient Yuuzhan Vong species, magma pebbles were inorganic objects. They consisted of a robust outer casing containing a small glob of magma, about the size of a thumbnail. These pebbles, compact enough to be held within a humanoid's hand, would heat up upon any kind of disturbance, such as being thrown. This heating would cause the outer shell to break away, releasing the molten rock payload. The magma within these white and orangey-red projectiles possessed sufficient potency to melt through the exterior of a YVH-Series battle droid and obliterate its internal circuitry within minutes.
As the most frequently used non-organic weapon of the Yuuzhan Vong warriors, magma pebbles were primarily utilized as projectiles against droids. The magma within the pebble was highly effective at corroding droid armor, disabling and destroying them. These pebbles were launched at targets, with the shell either disintegrating mid-flight or shattering upon impact, thus deploying the magma. Beyond their effectiveness against droids, magma pebbles could also be used against organic targets, as the molten substance could inflict extensive and severe burns.
By 27 ABY, during the Yuuzhan Vong War, the extra-galactic Yuuzhan Vong initiated their invasion of the galaxy belonging to the New Republic. During this time, the warrior caste employed magma pebbles against the droids deployed against them in battle. In that year, the bridge crew of the Yuuzhan Vong frigate Exquisite Death made a futile attempt to halt the battle droid 2-1S of the YVH-Series during a seizure of the ship by members of the New Jedi Order, utilizing magma pebbles and organic thud bugs. This attack, however, only resulted in pitting the droid's laminanium armor. Nevertheless, magma pebbles proved to be quite effective throughout the war in damaging YVH droids, which had been specifically designed to engage Yuuzhan Vong warriors.
Magma pebbles debuted in Troy Denning's novel Star by Star, which was the ninth book in The New Jedi Order series, released in 2001. The item was visually depicted in issue 111 of The Official Star Wars Fact File, which was released in 2004. The weapon was also documented in The Complete Star Wars Encyclopedia, published in 2008. However, this encyclopedia entry states that magma pebbles were filled with plasma rather than magma, as stated in the Fact File. This article considers the Fact File information to be accurate, as it provides a more detailed explanation of magma pebbles.