This works well for Monkeylord and pretty much any unit that is stealthed.
Before I send my Monkeylord to battle, I set the firing command to "Hold Fire" so that the enemy does not get alerted to its presence by seeing the Microwave Laser emerge from the fog of war and subsequently pull all of his units back.
This lets you walk right into the middle of bases while the enemy is busy looking elsewhere, and once you're in position, set the Monkeylord's firing status back to "Return Fire" and quickly get a veterancy badge or two.
I used this strategy successfully while my enemy was reclaiming some fallen experimentals with a bunch of T1 engineers. I set the ML to "Hold Fire", walked right on top of the engineers, and then started firing.
Did it again to a force of about twenty T2 bots who only started retreating when it was too late.