In Greek mythology, Phobos ("fright") was the personification of fear and horror. He was the son of Ares and Aphrodite. He, his brother Deimos, and the goddess Enyo accompanied Ares into battle. His Roman equivalent was Timor. Asaph Hall, who discovered the moons of Mars, named one Phobos.

In the centre [of the Shield of Herakles] was Phobos (Fear) worked in adamant, unspeakable, staring backwards with eyes that glowed with fire. His mouth was full of teeth in a white row, fearful and daunting, and upon his grim brow hovered frightful Eris (Strife) who arrays the throng of men ...

Upon the shield Proioxis (Pursuit) and Palioxis (Flight) were wrought, and Homados (Tumult), and Phobos (Panic), and Androktasie (Slaughter). Eris (Strife) also, and Kydoimos (Uproar) were hurrying about, and deadly Ker (Fate).

-Shield of Heracles 139f