A multiplatform title, listed as Endless Summer from Bethesda, was rated by Australia's Classification Board recently, according to a listing on the Board's website.
The Endless Summer listing, which is marked as "modified," carries an MA15+ rating with a warning of "Strong horror themes and violence."
Kotaku Australia notes that publishers often use codenames when publishing games. Bethesda are not commenting on Endless Summer.
Earlier this month, Bethesda's vice president, Peter Hines, said that the company aims to make "considerably more noise" in 2013 "as a publisher."