This odd item looks like the head of a morningstar, its blue spikes tipped with red cones, all banded together by a brass ring.
A burrowing ghost mine deals 5d6 damage in a 30-ft.-radius when detonated (no save). This damage affects incorporeal creatures as ghost touch, except that earth does not block line of effect.
A burrowing ghost mine can dig 50 feet straight down into the ground at a speed of 5 feet per round (the distance to burrow set when the mine is deployed). Once it reaches the desired depth, a burrowing ghost mine is armed and it explodes when any incorporeal creature passes within 30 feet of it.
Requirements Craft Magic Arms and Armor, 10 doses of black powder, 20 lbs of iron, plane shift, burrow; Cost 2,150 gp
[Part of Ludolog, the 2-Bit Dimension! –MM]