He tossed Frank his M16. For a split-second Frank thought he’d be crushed under the weight of the massive assault rifle, but the gun changed in midair, becoming smaller and thinner. When Frank caught it, the weapon was a spear. It had a shaft of Imperial gold and a strange point like a white bone, flickering with ghostly light.
“The tip is a dragon’s tooth,” Mars said. “You haven’t learned to use your mom’s talents yet, have you? Well—that spear will give you some breathing room until you do. You get three charges out of it, so use it wisely.”

The Son of Neptune, Chapter XII