Śatapatha Brāhmaṇa ("of a hundred paths") 11.7.3.2

11.7.3.2

atha yasyaitadvakrasya sataḥ śūla-ivāgram bhavati sa ha kapotī nāma sa yo ha tādṛśaṃ yūpaṃ kurute purā hāyuṣo'muṃ lokameti tasmāttādṛśamāyuṣkāmo yūpaṃ na kurvīta

And such a one as, while being crooked, has a top like a spit, is called 'kapotî '; and whoever makes such a one his sacrificial stake certainly goes to yonder world before his full measure of life: therefore let no one wishing for long life make such a one his sacrificial stake.