Siren Head is a very aggressive, monstrous and skilled predator, which makes him very dangerous. It seems to have some degree of intelligence due to using tactics such as camouflaging within forests and mimicking sounds like voices to hide from and lure his prey. Other than that, nothing much else is known about Siren Head’s way of thinking, though unconfirmed theories suggest it is the last of his kind and so might have a strong will to survive, possibly developing it's camouflage skills to hide from other dangerous creatures, though again this is not confirmed. Siren Head is not above fooling people with their friends’ voices and one sighting of him suggests that he also blocks out the screams of it devoured victims with his own sounds, ensuring there is no chance anyone will help them. This is most likely to ensure a successful hunt by confusing and disorienting the prey, though it might also simply be a form of cruelty. Siren Head also sometimes does not consume its victims as seen in the Siren Head video game, meaning that it possibly kills for sport or other reasons.
The latest possible sighting of Siren Head includes a news snippet of the aftermath of an unusual, never-before-seen killing tactic. For unknown reasons, Siren Head chose to kill many of the people in a town/neighborhood by bursting their eardrums and soft tissues. It is not known whether Siren Head produces a specific sound to cause such an effect, or if it simply made noises that were loud enough to do so. Many of the residents were left behind and not taken by Siren Head, suggesting that Siren Head has started killing large groups of humans just for the sake of it, which is odd as it has never performed such a sizable action before, usually only stalking and killing singular people or small groups at most. It is possible that this multi-headed version of Siren Head is a subspecies, or simply a design update, though Trevor has confirmed neither theory.