After the argument, he became like a porcupine in the office, and no one dared to approach him.

porcupine 是名词，指"豪猪"或"箭猪"，这种动物身上长满尖刺作为防御武器。在比喻用法中，形容一个人像 porcupine 表示这个人变得充满敌意或戒备心很强，就像豪猪竖起尖刺一样让人难以接近。