Skandapurana 1.4.24.72

1.4.24.72

ajñātakulatāṃ tasya pṛchyatāmayameva ca..
ahireva aheḥ pādānvetti nānyo himācala.. 26.72 ..

Let this one himself be asked about the fact that his lineage is unknown. / Only a snake knows the feet of a snake, no one else, O snowy mountain!