A creature that has gained the Stunned condition is aware of its surroundings but falls Prone and is incapable of taking actions or speaking.
Remedies
Taking damage after being stunned negates the condition. Also, succeeding an Easy DR Strength or Survival challenge roll removes the condition. Each time during combat that the same creature is stunned, the DR increases by one difficulty to remove. If the creature fails to remove the effect three times in a row after gaining the Stunned condition, it gains the Unconscious condition. A spell or ability may also be used to remove the condition.