The singularity cannon is the final weapon unlocked in the game. It is extremely hard to manufacture, using 25 alien alloys and a singularity core, only obtainable by defeating a battleship.
On top of this, the singularity cannon is mind-blowingly heavy, at 50kg it must be carried by a user of Predator armour. This is because Predator armour is weightless, increases your strength to 100 and decreases firing costs by 65%, making the TU firing cost under 100% from its previous 120% .
However, it has extreme power, blowing up almost entire rooms, especially useful against the High Praetor. Its damage is so high that it's guaranteed to kill any enemy in range of the blast, useful in many circumstances, especially when there are many enemies close together.