कालिय
Kāliya is the venomous serpent who, fleeing Garuḍa, left Ramaṇaka island and settled in a pool of the Yamunā, poisoning its water so that the cattle and cowherds who drank it died. Krishna leapt into the pool from a kadamba tree, danced upon his hoods and, having subdued him, ordered him away; at the prayer of the serpent's wives He granted him safety, sent him to the ocean, and promised that seeing the mark of His feet on his head Garuḍa would not molest him. SB 2.7.28 ties the act to the purification of the water — 'to purify it' — so that the aim of the chastisement is cleansing, not destruction.
Śrīmad Bhāgavata Mahāpurāṇa 2.7.28 — Sanskrit Wikisource (pinned oldid=200170)
When the cows were imperilled by drinking poison, Krishna subdued and raised the serpent-chief, and made the cows drink the water restored to its natural state: 'nigR^ihya bhujagAdhipam ... apAyayat gAs tat-toyaM prakR^iti-sthitam' (SB 3.2.31). The serpent-chief is named here by description, not by name.
