Monster hunt is Environmental Alert.
I actually meant Environmental Alert myself, but upon reflection both that and Zombie infestations have the drawback that the terrain is sourced from the globe, and thus you can't set it yourself in quick battles. Environmental Alerts also have very low enemy variety due to most cryptid species having only one or two different units.
Exobiological Contamination at least has a little bit of user-specifiable terrain variety, and can accommodate a range of units. OTOH, these might have enemies and also civilians with guns.
Personally, I'd set up my own testing mission for this, using a Battleship or similar as a base and deleting the UFO (and the plasma guns, if needed).