Porcupine
It is no wonder why the porcupine can carry its best defense mechanism literally on its back. However, one thing that is not well known is a secret weapon in case the prickly creature does not easily deter the predator.
If the pursuit continues, the porcupine will suddenly stop and let the enemy run headlong into them, causing a preemptive and potentially fatal blow. The predator will not even know what hit it until it is too late.