Flood Buddies

This can be done on any level with the Flood. It works particularly well with the Assault Rifle and Pistol. When you spot a Flood, shoot off its tentacled arm. On higher difficulties, you may also want to shoot off the elite infected flood's head, as this may be used as a weapon from time to time. If they are carrting a weapon, shoot off their right arm as well. Only the left arm must be amputated, and on Human infected flood, the head poses no threat. The arm in which they hold a weapon is only dangerous if they have a gun. After taking off teh left arm, and sometimes the head, the Flood are incapable of hurting you. This is great, as you may have them follow you just about everywhere. And if you don't want to make friends with them, you can use them as shields. But if you like them, you can give them names, and pretend to be able to tell them apart.