Devourer

A crystalline structure floating through the depths of space bears tidings of destruction: “The Devourer approaches!”
Countless cables, thousands of miles long, are lowered from the Devourer's inside wall to the Planet's surface below. An entire world is trapped, like a fly in the web of a cosmic spider. Giant transport modules are then sent back and forth between earth and Devourer, taking with them the planet's oceans and atmosphere.