When threatened, crested porcupines will raise and fan their quills to create the illusion of greater size and charge enemies back-first in order to stab them with their thick, short quills.
The quills of crested porcupines serve as an effective defense against predation. When disturbed, they raise and fan the quills to create an illusion of greater size. If the disturbance continues, they stamp their feet, whirr their quills and charge the enemy, back end first, attempting to stab with the thicker, shorter, sturdier quills.
Such attacks have been known to kill lions, leopard, hyaenas, and even humans.