The Ion Cannon is a special weapon of the game Star Trek: Armada. It inflicts a lot of damage when impacting an opposing ship. It is researched at the Weapons Center. It looks like this:

The Ion Cannon is also used by the campaign ships Martok's Negh'Var and Toral's Negh'Var. When trying to use this special weapon on a ship protected by a Corbomite Reflector, the damage will be reflected back to the casting ship. The Shield Remodulation on the other hand, protects from it, as well as an active Phase Cloak.