Mahabharata 1.3.138

1.3.138

praviśya ca nāgalokaṃ svabhavanamagacchat |
tamuttaṅko'nvāviveśa tenaiva bilena |
praviśya ca nāgānastuvadebhiḥ ślokaiḥ || 138 ||

"Now, Utanka, recollecting the words of the Queen, pursued the Serpent, and began to dig open the hole with a stick but was unable to make much progress. And Indra beholding his distress sent his thunder-bolt (Vajra) to his assistance. Then the thunder-bolt entering that stick enlarged that hole. And Utanka began to enter the hole after the thunder-bolt. And having entered it, he beheld the region of the serpents infinite in extent, filled with hundreds of palaces and elegant mansions with turrets and domes and gate-ways, abounding with wonderful places for various games and entertainments. And Utanka then glorified the serpents by the following slokas:

"On the road Utanka perceived coming towards him a naked idle beggar sometimes coming in view and sometimes disappearing. And Utanka put the ear-rings on the ground and went for water. In the meantime the beggar came quickly to the spot and taking up the ear-rings ran away. And Utanka having completed his ablutions in water and purified himself and having also reverently bowed down to the gods and his spiritual masters pursued the thief with the utmost speed. And having with great difficulty overtaken him, he seized him by force. But at that instant the person seized, quitting the form of a beggar and assuming his real form, viz., that of Takshaka, speedily entered a large hole open in the ground. And having got in, Takshaka proceeded to his own abode, the region of the serpents.