Monster-Proof Chalk

Quite simply, this is very expensive chalk that can be purchased from most vendors of magical exploratory goods. The chalk is impervious to most monster's scornful attempts to remove it; it requires more effort than that. Those with attempts to remove the chalk will get a burning, acidic feeling. In addition, powerful extraneous conditions such as wind and heat are also negated. It is used to mark the side of dungeon tunnels.

Cost: 4000 GP per 4-inch chalk section, 1200 GP for a one-inch (bulk discount for the 4-incher).