Keerthimukha's Moodha Bhakthi
Jalandhar, a rakshasa, was overcome with pride and arrogance because of his conquests, and the boons he received from Brahma and Vishnu. He sends Rahu as a messenger to Shiva, telling him to give Parvati to him, as he intends to marry her.
When Rahu goes to Shiva and conveys the message, Shiva gets angry and creates a demon in the form of a lion from his third eye, and commands it to devour Rahu.
Rahu gets extremely scared and asks Shiva for forgiveness, claiming to be nothing but a messenger. Shiva calms down a little, and forgives Rahu. However, the demon born to eat Rahu is with extreme hunger and asks Shiva to feed him again and again, pestering him.
Annoyed, Shiva tells him to eat himself and slips into meditation. After a moment he hears crunching sounds, opens his eyes to see the demon devouring himself, with only face left.
Pleased with his Moodha bhakti, Shiva names him Keerthimukha, and gives him a boon that anyone visiting any temple will first have to have a darshan of him and only then darshan of the god in Garbha Griha.
Image Source: jabumbum
We still find Keerthimukha on the wall of entrance of Garbha Griha. Faith is such a powerful tool that it chisels the paraphernalia surrounding our Aatma and helps merge into Paramatma.
Such a beautiful story from SKANDA PURANA.