According to Shat Rudra Sanhita (5/2) of Shiv Puran, Parmeshwar Sadashiva took an Avatar of Lord Bhairava on Margshirsh Krishna Paksha Asthami hence he must be worshiped as Shakshat Shiva
भैरव: पूर्णरूपो हि शंकरस्य परात्मन:।
मूढास्तं वै न जानन्ति मोहिताश्शिवमायया।।
Translation- Bhairava is Completely Shiva, Ignorant don’t recognise this due to delusion by Maya of Shiva.
The ancient text Shakti Sangam Tantra in its Kali Khand chapter has mentioned the origin of Lord Batuk Bhairav. According to the text, once a demon named Aapat had gained powers through Sadhanas and he used it to harass everyone including the gods.
The gods then got together and started to think of ways to find a solution to this problem. As they started concentrating, their powers appeared as a flash of light and took the form of a five year old child, Batuk. The child, then, killed the demon and saved the gods which is why he is known as Aapat Uddharak Batuk Bhairav.
In tantra and other Hindu puja, this is the most worshiped form of Lord Bhairav among the various forms of Bhairav. All other forms of Bhairav are terrifying apart from this as this is in the form of a child. He is also known as the child form of Lord Shiva. The image of Batuk Bhairav is displayed with a dog accompanying him, which is symbolized as dharma.
He is said to be pleased by the devotion of the worshippers and conducting puja and homam is said to take away all the obstacles and cleanse the soul. Also, the dogs, especially the black dogs are considered to be the form of Bhairav and feeding the dogs every Saturday and taking care of them is also said to please the god and bring good fortune.
Worship of any mahAvidyA is incomplete without the propitiation of vaTuka: the bhairava in the form of a brahmachArin youth. It is stated in skandayAmaLa that among the nine essentials for mantra-siddhi, guru, gaNapati and vaTuka are of primary importance without their grace, parAshakti is not pleased with the sAdhaka. While vaTuka has sAttvika, rAjasika and tAmasika forms based on kriyA-bheda, he is popularly depicted as below:
वटुकं बालवेषं च नागयज्ञोपवीतिनम् |
कपालशूलभूषाढ्यं स्वयूथैः परिवेष्ठितम् ||
कुक्कुरैर्नववर्णैश्च वेष्टितं ब्रह्मरूपिणम् |
द्वादशारस्थितं देवं प्रत्यक्ष्यफलदं कलौ |
प्रेतासनसमासीनं त्रैलोक्यजयदं भजे ||
vaṭukaṃ bālaveṣaṃ ca nāgayajnopavītinam |
kapālaśūlabhūṣāḍhyaṃ svayūthaiḥ pariveṣṭhitam ||
kukkurairnavavarṇaiśca veṣṭitaṃ brahmarūpiṇam |
dvādaśārasthitaṃ devaṃ pratyakṣyaphaladaṃ kalau |
pretāsanasamāsīnaṃ trailokyajayadaṃ bhaje ||
The origin of the mUrti named vaTuka is described variously in the tantras. The shAkta version is presented here. It is said, that at some point in the present kalpa, the universe was permeated with various beings such as vetAla-s, preta-s, pishAcha-s, kUShmANDa-s, yakSha-s, rAkShasa-s, kinnara-s, gandharva-s and grahas of various categories such as brAhma, vaiShNava, raudra, aindra, gANapatya, kaumAra, pAshupata and saura. While being devoted to a particular deity (such as gANapatya grahas to gaNapati and his upAsakas), they also created havoc and robbed sAdhakas of the merit of their japa and worship. To protect the world and the well-being of upAsakas, bhagavatI AdyA mahAkAlI conceived the divine form of vaTuka:
वेतालाद्या महादेवि जपपूजादिहारकाः |
तेषां विनाशनार्थाय भक्तानुग्रहणाय च |
वटुकोऽयं महेशानि महाकाल्या विभावितः ||
vetālādyā mahādevi japapūjādihārakāḥ |
teṣāṃ vināśanārthāya bhaktānugrahaṇāya ca |
vaṭuko.ayaṃ maheśāni mahākālyā vibhāvitaḥ ||
The form and essence of vaTuka bhairava were derived from the tejaH of innumerable forms of yoginI-s, bhairava-s, mahAvidyA-s and various manifestations of kAlI, tArA, tripurasundarI, bAla, ChinnamastA, bagalAmukhI, bhuvaneshvarI, dhUmAvatI and mAta~NgI.
पञ्चाशत्कोटिगणना योगिनीनां तु कोटिशः |
भैरवाणां कोटिकोटिर्महाविद्यास्त्वनेकशः ||
त्रिखर्वसंख्या तारा स्यात् काली दशार्बुदा शिवे |
कलाकोटिप्रभेदा तु सुन्दरी तेन संयुता ||
बाला त्रिकोटिसंख्याभिश्छिन्ना षोडशखर्वतः |
कोटिद्वादशभिर्देवि भुवनांशेन पार्वति |
धूम्रकला लक्षभेदैः सिद्धविद्याख्यतत्त्वतः ||
चतुरशीतिलक्षैश्च मातङ्गीमन्त्रतः शिवे |
एतत्सर्वमयं तेजः सर्वब्रह्माण्डरूपधृक् |
सर्वतेजःसमुद्भूतं वटुरूपं सनातनम् ||
pancāśatkoṭigaṇanā yoginīnāṃ tu koṭiśaḥ |
bhairavāṇāṃ koṭikoṭirmahāvidyāstvanekaśaḥ ||
trikharvasaṃkhyā tārā syāt kālī daśārbudā śive |
kalākoṭiprabhedā tu sundarī tena saṃyutā ||
bālā trikoṭisaṃkhyābhiśchinnā ṣoḍaśakharvataḥ |
koṭidvādaśabhirdevi bhuvanāṃśena pārvati |
dhūmrakalā lakṣabhedaiḥ siddhavidyākhyatattvataḥ ||
caturaśītilakṣaiśca mātaṅgīmantrataḥ śive |
etatsarvamayaṃ tejaḥ sarvabrahmāṇḍarūpadhṛk |
sarvatejaḥsamudbhūtaṃ vaṭurūpaṃ sanātanam ||
From the congregation of the tejaH or luminous essence of those myriad deities was born the mUrti of vaTuka bhairava due to the samkalpa of AdyA mahAkAlI. He was endowed with the energies of the trimUrti-s and their corresponding shakti-s, earning him the name guNatrayasvarUpavAn (sattva, rajaH and tamas). Based on predominance of sattva, rajas or tamas, vaTuka appears in three major forms. However, based on the predominance of one of the ten mahavidyA-s who constitute his form, he also appears in ten forms propitiated by the shAkta-s.
After the appearance of vaTuka, he was gifted with an upavIta by ugratArA. He was awarded a kapAla by ChinnamastA and granted the mastership of time and death by kAlikA. He was also given a trishUla with its three prongs presided over by shaktitraya – kAlI, tArA and ChinnamastA. Categories of various beings such as siddha-s, sAdhyas etc. assumed the form of nine dogs and began to serve vaTuka. It was then revealed by mahAkAlI that it was shiva, based on her samkalpa, who had materialized as vaTuka and would henceforth be referred to as ‘devIputra’, reasserting her status as jagadyoni. vaTuka gained control over vetAlAdi grahas and by propitiating him during one’s upAsanA, the sAdhaka is not bothered by any malevolent graha and is protected from every kind of distress and danger.
The jayantI tithi of vaTuka bhairava is shuddha-dashamI of jyeShTha mAsa.
The esoteric aspect of vaTuka is described thus by mahAmAheshvara abhinavaguptapAdAchArya:
अपहृतविनयजनार्तिं वटुकमपादानाभिदं वन्दे ||
apahṛtavinayajanārtiṃ vaṭukamapādānābhidaṃ vande ||
बटुक भैरव ध्यानः-
कर-कलित-कपालः कुण्डली दण्डपाणिस्तरुण-तिमिर-नील वर्णो व्याल-यज्ञोपवीती ।
क्रतु-समय-सपर्या-विघ्न-विच्छेद-हेतुर्जयति बटुकनाथः सिद्धिदः साधकानाम् ।।
The jayantI tithi of Batuka bhairava is shuddha-dashamI of jyeShTha mAsa.
His Priya Bhog is Doodhpak and Vada or Pakoda of Arad fried in Tal tel or Sarsav, Sometimes bundi laddoos.
Source: Rakeshbhai Vyas London and Harshadanandji (Nirvana Sundari Group)