A sub-genre of metal, in which the vocals are said in a similar fashion to Gollum from Lord of the Rings. This can involve quiet, drawn out vocals, and low screams. This genre is often associated with the Australian band, Forgetting Skaro, who is said to have created the genre.
"I wonder what Gollum would sound like if he was in a band."
"Just listen to Forgetting Skaro, a gollumcore band."