The statue is similar to the Javanese Kala, and was intended to protect the temple complex from malevolent spirits.
In Balinese mythology, Bhoma is the son of Dewa Wisnu and Dewi Pertiwi, the god of rain and the goddess of earth.
The figure of Bhoma that was produced by this union is seen as the growth of vegetation or forest (Vanaspati) as a result of the earth receiving the (rain) water.
In this context, the head of Bhoma at the base of the padmasana symbolizes the forest which surrounds the foot of a mountain (batur pepalihan).
[1] In some Balinese houses, the doorway to some enclosed pavilion (e.g. the bale meten) is decorated with ornaments to form a ventilation grill which is sometimes paneled.