Bhairava is the name of a fearsome aspect of Shiva. He is known as the Lord of Magick. Bhairava is seen as a type of gatekeeper. That is, He keeps away those who who cannot or must not enter. It is for this reason he is often seen as displaying very impressive fangs.

Bhairava will accept almost any offering, even if deemed impure by other Devas. What differentiates the success of the offering is the intention of the one offering it.

Further reading
Sri Kapilnath (2004). Bhairava in The Open Door.
Dhruvanath (2007). The Lingam of Lord Bhairava in The Open Door.