Superweapon built by the Xindi to destroy Earth, whose 2153 prototype killed seven million people before Enterprise stopped the finished weapon in 2154.
The Xindi weapon was a planet-destroying device built by the Xindi Council after the Sphere-Builders convinced them that humans would destroy their people in the future. It was designed largely by the Xindi-Primate scientist Degra, and in its finished form it was a large self-propelled vessel able to reach Earth through a subspace vortex.
A smaller prototype was launched against Earth in 2153, carving a path of destruction from Florida to Venezuela and killing about seven million people. The attack, which opens The Expanse, sent Enterprise into the Delphic Expanse to find the Xindi and stop the full weapon before it could be used.
Over the following year, Archer's crew disrupted the weapon's development and won over Degra and other council members. In Zero Hour, the Reptilians and Insectoids launched the finished weapon toward Earth, and Archer led a team aboard and destroyed it while the Enterprise crew destroyed the Sphere-Builders' network of spheres.