Unsustainable Rage

After the first turn of activating Rage, you gain a plus to damage equal to your level (level 2 = +2 damage) to damage each turn that stacks (lvl 1; second turn = +1, third turn = +2, etc.). 

However, each turn you are in Rage after the first, you lose 1 Point in Intelligence (second turn 13 INT -> 12 INT, third turn 12 INT -> 11 INT).