The Vorl-tak - the world weapon - was a powerful ancient Vulcan psionic weapon. One was never built on Vulcan before as it was considered to dangerous, possibly destroying the planet as it fired, and such weapons were outlawed. However on the lost Vulcan colony of the Last-of-all-Cities on Darien 224 one was built.
The Vorl-tak used the host planet's gravitational field as a psionic amplifier, to channel raw emotion into a powerful energy beam. The components of the Vorl-tak can also be used to build an impulse engine.
The Vorl-tak was used once by the Last-of-all-Cities, and successfully destroyed it’s target the USS Cortez. However the aftershock of the firing began to destroy Darien's crust. Within minutes, the Vorl-tak, the Tabernacle of sharp conflict in which it was housed, the Last-of-all-Cities and the entire surface of Darien 224 were destroyed, the crust of the planetoid shattering and sinking into the magma layer. (EV comic: Cloak and Dagger)