when cast the spell will stop time for 10 second or one round for everything ally enemy animal object and will  dispel all spell with in range if you roll nat 20 the time is doubled you can make another action the same round at the end when the spell end roll 1d20 if you get 19 or higher with CON mod you get another round  if you roll nat 20 the time is doubled effect only work once every time the spell is cast also every one who is affected by the spell are not aware of what happening and yes this a jojo reference