Once the creature is seized, the next round the ankheg will back away half its movement rate (4 hexes) from any threat, crushing its prey in its pincers for 2-12 damage and simultaneously spraying the victim with acid for 4-32 additional damage. The ankheg can squirt acid only once per day. The ankheg will continue to back away at 4 hexes per round thereafter until the victim is unconscious or dead, whereupon the ankheg will flee with its capture until it is 30 hexes away from any threat. At this point the ankheg will drop its prey and begin to devour it - except during the month of December, when the ankheg will bury the victim in the earth and inject it with thirty eggs. The ankheg will then move on to seek other food. The eggs will hatch in 3-4 weeks, devouring the victim and growing into 3 hit dice ankhegs.
When occurring, ankhegs will be widely scattered; there is only a 1 in 6 chance that two will be encountered together, typically buried 13-20 hexes apart. Others of the 1-6 appearing might be anywhere within the encounter hex.