Mahabharata 1.3.53

1.3.53

atha tasminnanāgacchatyupādhyāyaḥ śiṣyānavocat |
mayopamanyuḥ sarvataḥ pratiṣiddhaḥ |
sa niyataṃ kupitaḥ |
tato nāgacchati ciragataśceti || 53 ||

"And Upamanyu, one day, oppressed by hunger, when in a forest, ate of the leaves of the Arka (Asclepias gigantea). And his eyes being affected by the pungent, acrimonious, crude, and saline properties of the leaves which he had eaten, he became blind. And as he was crawling about, he fell into a pit. And upon his not returning that day when the sun was sinking down behind the summit of the western mountains, the preceptor observed to his disciples that Upamanyu was not yet come. And they told him that he had gone out with the cattle.