The Steel Dragon trap is featured in the Zombies in Spaceland map. When activated a laser beam will form a line across the hallway, burning and killing any zombie that passes through.
The trap can be found in Polar Peak next to a RPR Evo wall buy.
Wonder Weapon Part
Killing enough zombies with this trap after releasing the UFOs from inside the Projector Room can lead you to getting a part for the Headcutter Wonder Weapon.
The player needs it to get the X-Quisite weapon attachment.