How To Defeat The Homunculus (Fetus Biomech AKA "General Krang") With A Tool Gun

Using only the bio-tool gun in my opinion is better than using the other weapons in the Scorn player's inventory for defeating the first Homunculus (fetus biomech or "General Krang"). For the second Homunculus you don't have a choice but use the grenade launcher against it, and it can be defeated by using only 2 grenade shells.