Primeape (3.5e Monster)

Combat
 (Ex): If a Primeape cannot see another Primeape (or Mankey), and can see any other creature it flies into a destructive rage. While enraged, it gains phenomenal strength and durability but becomes less able to defend itself. It temporarily gains +6 to Strength and Constitution, and a +3 morale bonus on Will saves, but suffers a -2 penalty on AC.

While raging, the Primeape cannot use any skills or abilities that require patience or concentration, such as moving silently or casting spells. A fit of rage lasts until the Primeape cannot see any non-Primeape creatures for 3 consecutive rounds, after which the Primeape is exhausted and falls asleep for 8 hours. A Primeape can enter depthless fury if it is fatigued, but not if it is exhausted.