Adrenaline Rush

Adrenaline Rush is a perk in Fallout 2, Fallout Tactics and Fallout 2d20. It was also a skill that was to appear in the canceled Fallout: Brotherhood of Steel 2.

Fallout 2d20
When one's health is below its maximum value, count one's Strength score as 10 for all purposes when attempting a Strength-based skill test or melee attack.

Fallout: Brotherhood of Steel 2
When HP drops below 40% Melee attacks do more damage.

Behind the scenes
The perk Nerd Rage! is similar to Adrenaline Rush, and uses a variation of the image.