Different resources list slightly different variations of bhairavasana. One variation the pose is entered into from kapilasana, by releasing the grip and reclining backwards. The drishti is to the third eye. In another variation, the leg is kept behind the head, but the body is held in a side plank position. Both variations of bhairavasana require a significant degree of openness and flexibility in the hips and hamstrings.
It is said that the reward of this pose is sublime serenity. Pattabhi Jois, the founder of Ashtanga yoga, referred to this asana as kashyapasana.