A Roman dodecahedron.
A dodecahedron is a twelve sided device meant to trap or freeze monsters, demigods, and legacies in place.
Description[]
Dodecahedrons are twelve sided, resembling dice from role playing games, that are meant to immobilize monsters and anyone with devine blood. If one is used, the victim is frozen in place. If three or more are used, they create an airtight barrier that is impossible to escape unless they are disarmed.
The Nico di Angelo Adventures[]
The Court of the Dead[]
As Johan is working in Camp Jupiter's archives, Lucius Silver demands that the blemmyae gives him one. However, the son of Mercury attempts to trap Johan with it. However, it backfires and the demigod is frozen in place. He calls Nico di Angelo to disarm it and, after Lucius is freed, he runs away.
Later, when Pirithous, Tantalus, and Mary Tudor plan to overthrow Hades, they use four dodecahedron to close off an area of Golden Gate Park to trap mythics in an attempt to overload the Mist. The prisoners try whatever they can to escape.