Monotanium

Monotanium was a metallic alloy typically used in the armor plating of Hirogen warships and space stations. It also had the added effect of scattering targeting beams. 

On their first encounters, USS Voyager's weapons were relatively ineffective against the Hirogen ships' armor. 

An Entharan target buoy used to demonstrate Kovin's isokinetic cannon was made from ten meters of solid monotanium. 

Monotanium