The Final Stand in action. Notice the player downed by Zombies and he has a primary weapon.
The Final Stand perk icon
Final Stand is a non-canonical Perk-a-Cola that appears in some custom Zombie maps. When downed it's effects make you stronger, so you are able to use a primary weapon and also allows you to use Special grenades, Monkey Bombs, Gersch Device and Matroyshka Dolls. It costs 1000 points.