Portable Earthworks

A portable earthworks is a stubby metal spike jacketed in copper. When buried, it causes an oblong vertical wall 6 feet high, 4 feet wide, and 2 feet thick to spring upward out of the ground. The wall will be made of whatever material the portable earthworks was immersed into: soil, brick, stone, concrete. It will even work in sand, the device's power supply creating an ever-shifting barrier. Portable earthworks will not function in wood or metal. A strong person can usually deploy a portable earthworks quickly by simply hurling the spike forcefully into the ground; however, depending upon the material, it may be necessary to hammer the spike into place like a piton. The wall created by a portable earthworks generally lasts around 1 hour before crumbling, at which point the device may be retrieved, recharged, and used again.