Blood Rage

Choose two willing creatures within range, they become angrier as they fight. Affected creatures gain a cumulative +2 bonus to Strength and a cumulative -1 penalty to AC each time they hit with an attack or take damage(maximum twice per round and with a maximum +10 strength, -5 AC) for the duration of the spell. The effects fade if the target falls unconscious.

Using a Higher-Level Spell Slot: When you cast this spell using a spell slot of 5th level or higher, you can target one extra creature and the bonuses can apply an additional time for each level above 4th.

Port of Pathfinder first edition spell Blood Rage.