I released the alpha with this property included. I forgot to include the updated imp.cfg which commented the new property, but it functions all the same.
Code:
; Creature properties
; BLEEDS - the creature leaves blood when is hit, slapped, dying or being injured in any way
; UNAFFECTED_BY_WIND - the creature isn't pushed back by Wind spell
; IMMUNE_TO_GAS - the creature isn't injured by Gas Traps and Farts
; HUMANOID_SKELETON - the creature leaves a skeleton if left in prison to die
; PISS_ON_DEAD - creature feels urge to piss on nearby dead bodies
; FLYING - creature normally isn't touching ground when moving and can move up and down
; SEE_INVISIBLE - creature has natural ability which works like Sight spell
; PASS_LOCKED_DOORS - creature can move through locked doors and won't fight with doors
; SPECIAL_DIGGER - creature can dig and perform other dungeon tasks
; ARACHNID - creature is kind of spider
; DIPTERA - creature is kind of fly
; LORD - creature is lord of the land, usually arrives to level as final boss, and at arrival
; you can hear "beware, the lord of the land approaches"
; SPECTATOR - creature is just a spectator for multiplayer games
; EVIL - creature has evil nature
; NEVER_CHICKENS - creature isn't affected by Chicken spell
; IMMUNE_TO_BOULDER - when boulder trap hits the creature, falls apart without dealing any damage
; NO_CORPSE_ROTTING - Creature body can't be taken to rot on graveyard
; NO_ENMHEART_ATTCK - Creature won't attack enemy dungeon heart on sight
; TREMBLING_FAT - Creature is so fat that ground trembles when it falls
; FEMALE - Creature is a female, does female sounds and has female name
; INSECT - Creature is an insect (note that DIPTERA and ARACHNID creatures should also have INSECT set explicitly)
; ONE_OF_KIND - Only one creature of that kind may exist on a specific map. Creature name is set to kind name.
; NO_IMPRISONMENT - Creature cannot be stunned for prison.
; IMMUNE_TO_DISEASE - Creature cannot get diseased
Properties = BLEEDS SPECIAL_DIGGER EVIL NO_ENMHEART_ATTCK