SB 3.6.25
atmanam casya nirbhinnam
abhimano ’visat padam
karmanamsena yenasau
kartavyam pratipadyate
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Thereafter the materialistic ego of the gigantic form separately manifested itself, and into it entered Rudra, the controller of false ego, with his own partial activities, by which the living entity transacts his objective actions.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The false ego of materialistic identity is controlled by the demigod Rudra, an incarnation of Lord Siva. Rudra is the incarnation of the Supreme Lord who controls the mode of ignorance within material nature. The activities of the false ego are based on the objective of the body and mind. Most persons conducted by the false ego are controlled by Lord Siva. When one reaches a finer version of ignorance, he falsely thinks of himself as the Supreme Lord. That egoistic conviction of the conditioned soul is the last snare of the illusory energy which controls the entire material world.