Atharvavedaparishishta 3.1.10

3.1.10

yasyānyakulopayuktaḥ purodhāḥ śāntikapauṣṭikaprāyaścittīyābhicārikanaimittikordhvadehikāny atharvavihitāni karmāṇi kuryāt sa tasya pratyaṅgiro bhūtvā hastyaśvarathapadātikaṃ prakṛtimukhebhyo ...

If a royal domestic priest who was employed by another family performs for him the pacifying, nourishing, expiatory, sorcerous, omen-prompted, and funerary rites prescribed by the Atharvan, he, becoming an adversary (pratyaṅgiras) to him, [destroys] the elephants, horses, chariots, and infantry from the foremost ministers...