Quake Grunt. Constant look of constipation on face, makes a noise like he's vomiting. Fairly pitiful.
Warcraft Grunt. Definitely the more badass looking of the grunt family, nice big teeth and and a willingness to kamikazee.
3. Covenant Grunt
Halo Grunt. Probably the most amusing of all bottom tier enemies. Known to shriek in terror and run away at the first sign of danger. Quite pitiful and stupid as all hell yet somehow lovable.