One of the most beautiful and popular names given to Lord Shiva is Pashupatinath. It literally means "master of animals." However, this epithet of animals includes every Being. Dwi pada, chaturpaada, and bahupaada mean two-legged ones, four-legged ones, and multi-legged ones, respectively. So, we also included Pashu Iti Pashyati. In the Vedas, it's said that a Pashu is the one who looks outside, which connotes that the person who is looking outwards is behaving like a Pashu, a mere animal. However, when he starts looking inward, he becomes Pashupati. Shiva is in deep penance. Happy Maha Shivaratri!