आगमे शैवे विश्वासटिप्पन्यः

Source: TW

The pAshupata-tantra is notable in providing a full uddhAra of the famed vyomavyApin mantra. It is mostly thought to be a unique mantra of the saiddhāntika-s. One could argue that the pAshupata-tantra being a late expression of the pAshupata-s borrowed this mantra from the saiddhAntika-s. However, we believe it emerged among the later pAshupata-s (i.e., subsequent to their Vedic representatives) but prior to the branching off of the streams of the mantra-mArga like the saiddhAntika-s. Our main reasons for holding this view are:

Within the saiddhāntika tradition it is remarkable in showing some diversity suggesting that emerged from the pre-saiddhāntika ``atimArga’’ matrix. This means it had already diversified within the prayoga traditions from which the siddhAntAgama-s inherited it.
In terms of its structure it is more removed from the later bIja-rich mantra and closer to the mantra-s of the transitional mantrashAstra, viz., at the junction between the vaidika- and the full-blown tAntrika mantramArga.
Its dhyAna-s describe a 14- and 10- handed rudra distinct from sadAshiva the devatA of the saiddhAntika version.

The core without the kavacha & aghorAstra- sampuTikaraNa-s is said to follow the 14 handed dhyAna:

वसिष्ठ ऋषिः । गायत्री छन्दः । परमेश्वरो देवता ॥
शूलाहि-टङ्क-घण्टासि–
रणड्-डमरुकं क्रमात् ।
वज्र-पाशाग्र्य् अभीतिं च
दधानं कर-पल्लवैः ॥
कपालम् अक्षमालां च
शूलं खट्वाङ्गम् एव च ।
एवं ध्यात्वा प्रभुं दिव्यं
ततो यजनम् आरभेत् ॥

With the kavacha & astra the dhyAna is the fierce 5-headed 10 handed rudra:

कल्पान्तार्कं सहस्राभं
रक्ताक्तं रक्तवाससं ।
दंष्ट्राकराल-संभिन्नम्
पञ्चवक्रम् भयङ्करम् ॥
केशैश् च कपिलैर् दीप्तं
ज्वालमाला-समाकुलम् ।
टङ्कं चर्म कपालं च
चापं नागं च वामतः ॥
शूलं खड्गं युगान्ताग्निं
बाणं वरदम् एव हि ।
दक्षिणैः स्वभुजैर् दीप्तं
रुद्रं ध्यात्वा यजेत् प्रभुम् ॥

The core mantra (i.e., without kavacha & astra) is exactly 365 syllables. The versions from saiddhAntika texts from South India have more than 365 – 368-374 typically. We believe the pAshupata versions is close to the original as the old saiddhAntika text described rudra embodied by this mantra as “saMvatsara-sharIriNaH”. This would also be consistent with 9-fold maNDala taught by the Kashmirian mantravAdin bhaTTa rAmakaNTha-II & followed by his southern successors: this would imply 40 syllables along each spoke & the pa~ncha-praNava at the nave.