As tall as a dwarf, this crab-like creature is has oversized pincers and a carapace covered with strange runes.
AC 20, touch 13, flat-footed 17 (+3 Dex, +7 natural)
Speed 30 ft., swim 20 ft.
Str 19, Dex 17, Con 18, Int —, Wis 14, Cha 6
Environment any aquatic or coastline
Repulsive Runes (Su) The magical runes on the body of a runeshell emit sporadic bursts of repulsive force when the runeshell is struck in combat. Whenever a creature hits a runeshell with a melee attack, the runeshell may expend an attack of opportunity to perform a bull rush combat maneuver against that creature (if that creature is within the runeshell's reach) and that creature may expend an attack of opportunity to perform a bull rush combat maneuver against the runeshell. These maneuvers don't provoke attacks of opportunity. Any bull rush combat maneuver performed as a result of this ability counts as a force effect. If the maneuver is successful, the creature making the bull rush attempt cannot choose to move with the target.