An ankheg usually lies 5 to 10 feet below the surface until
its antennae detect the approach of prey. It then burrows up to
attack. (Treat this as a charge.)
Improved Grab (Ex): To use this ability, the ankheg must hit
with its bite attack. If it gets a hold, it deals automatic bite
damage each round the hold is maintained. If the ankheg is
damaged after grabbing its prey, it retreats backward down its
tunnel at burrowing speed, dragging the victim with it.
Acid (Ex): Acidic enzymes drip from an ankheg's mouth
each round it maintains a hold. It automatically deals 1d4 points
of acid damage each round in addition to bite damage.
Spit Acid (Ex): Stream of acid 5 feet high, 5 feet wide, and
30 feet long, once every 6 hours; damage 4d4, Reflex half DC 14.
One such attack depletes the ankheg's acid supply for 6
hours. It cannot spit acid or deal acid damage during this time.
Ankhegs do not use this ability unless they are desperate or
frustrated. They most often spit acid when reduced to fewer than
half their hit points or when they have not successfully grabbed
Tremorsense (Ex): Ankhegs can automatically sense the location
of anything within 60 feet that is in contact with the ground.