The Impact Cannon is a large, green, rectangular cannon.
In order for it to run properly, it must be given Water, a diamond, an emerald, and lastly a block of redstone.
When activated it will begin to smoke, and the water in it's water tank will begin to drain. It will spray steaming hot water streams from it's front, that do 2 hearts of damage upon contact. It will then shine a red beam at it's target, then the beam will disappear, and the cannon will fire a short green ray of light. Upon contact, the ray of light will create an explosion the size of an endercrystal explosion.
The canon itself cannot be broken, but it can be turned into a mobile mode, allowing it to be moved about. It will not work at all without the proper materials, and if used with all of them, but without water, it will light itself and the ground around it on fire, and spew fireballs instead of boiling water.
It's current location has not been discovered, but it is thought that it is located in the Aetherical Fortress or Void fortress.