SB 3.12.16
rudranam rudra-srstanam
samantad grasatam jagat
nisamyasankhyaso yuthan
prajapatir asankata
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The sons and grandsons generated by Rudra were unlimited in number, and when they assembled together they attempted to devour the entire universe. When Brahma, the father of the living entities, saw this, he became afraid of the situation.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The generations of Rudra, the incarnation of anger, were so dangerous to the maintenance of universal affairs that even Brahma, the father of the living entities, became afraid of them. The so-called devotees or followers of Rudra are also a menace. They are sometimes dangerous even to Rudra himself. Descendants of Rudra sometimes make plans to kill Rudra — by the grace of Rudra. That is the nature of his devotees.