Shiva As Ardhanarishwar and eight idols of Shiva

EIGHT IDOLS OF SHIVA
After describing about the five chief incarnations of lord Shiva, Suta explained about the eight famous idols of lord Shiva- Sharva, Bhava, Rudra, Ugra, Bhima, Pashupati, Ishan and Mahadeva. These eight idols of Shiva symbolizes the eight natural elements which help in the process of creation, nurturement and annihilation. These eight natural elements are Land, water, fire, air, sky, supreme soul (Kshetragya), Sun and the moon. Being established in these eight idols, Shiva controls the whole world. 

SHIVA AS ARDHANARISHWAR- Accordig to Shiva Purana

Once upon a time Lord Brahma, not seeing an expansion in his creation became very worried. A heavenly voice instructed him to commence creation with the help of copulative activities. But since all the incarnation of Shiva had been males till then, therefore lord Brahma was finding it impossible.


Lord Brahma contemplated on the form of Shiva and Shakti. Lord Shiva became very pleased with him and appeared in his form of 'Ardhanarishwar (half male half female)
 Left side of his body resembled like a woman while the right side appeared like a man.
 Lord Brahma worshipped this form of Shiva. 
Lord Shiva then separated the feminine part of his body and thus manifested mother Shakti. Lord Brahma worshipped her and requested to bestow such power by which he could create a woman. 
Goddess Shakti blessed him by saying - 'So be it' and vanished. This way Lord Brahma became capable of commencing copulative creation.

SHIVA AS ARDHANARISHWAR -  According to Linga purana

 Lord Brahma did an austere penance to please Lord Shiva. Shiva manifestated as Ardhnarishwar (partly male partly female) from his forehead and said--'I am your son'.

But, the unberabale heat emanating from the effulgence of Ardhanarishwar burnt the whole world including Lord Brahma.
Lord Shiva then separated the feminine part of his body (Goddess Parmeshwari) and instructed her to begin creation. Both Brahma and Vishnu manifested from the body of goddess Parmeshwari. Lord Vishnu divided his body into two halves and created the world. Lord Brahma once again did a tremendous penance which lasted for ten thousand years. Once again Shiva manifested from his forehead, but this time as Neelalohit. Lord Neela Lohit became pleased by Brahma's eulogy and blessed him.