This is a mean artifact.

Crustal Diffuser - 50 energy to use on an enemy planet
Usable only if you have the ability to invade a planet (both an available slot, and not be on countdown from an invasion)

Random 50% chance to destroy any given structure on a planet. Alerts both legions (if a member) to the use of the device. Resets the invasion counter as if this were a failed invasion.

There's already an artifact similar to this in the game, called a Crimson Cluster Missile.

"Destroys one standard Defense, Attack, or Population structure at random on an enemy planet. "

It's from the mission "Crimson Cluster Project".

but this "Crustal Diffuser" has 50/50 chance for each building. It could wipe the planet clean or possibly do nothing.

Ah, ok. I wasn't sure what your intent was the way you described it. that could be a real Sword of Damocles to use, especially if the world you wanted to invade had alot of mission artifact structures on it.