Grimlocke's post inspired me to play around with another, slightly sillier way of not surviving HFS.
Behold, the terrifying slade pebble:
[CREATURE:SLADE_PEBBLE]
[DESCRIPTION:An animate, burning stone chipped from the bedrock of Hell itself. Now you will know why mining slade is forbidden.]
[NAME:slade pebble:slade pebbles:slade pebble]
[CASTE_NAME:slade pebble:slade pebbles:slade pebble]
[CREATURE_TILE:'.'][COLOR:0:0:1]
[BIOME:SUBTERRANEAN_CHASM]
[UNDERGROUND_DEPTH:5:5][POPULATION_NUMBER:1:1][CLUSTER_NUMBER:1:1][FREQUENCY:75]
[LIKES_FIGHTING]
[LARGE_PREDATOR]
[NOBONES]
[NO_GENDER]
[BUILDINGDESTROYER:2]
[PREFSTRING:density]
[BODY:BASIC_1PARTBODY_THOUGHT]
[NO_THOUGHT_CENTER_FOR_MOVEMENT]
[SPHERE:DEATH]
[EVIL]
[HOMEOTHERM:20500]
[TISSUE:SLADE]
[TISSUE_NAME:slade:NP]
[TISSUE_MATERIAL:INORGANIC:SLADE]
[MUSCULAR]
[FUNCTIONAL]
[STRUCTURAL]
[RELATIVE_THICKNESS:1]
[CONNECTS]
[TISSUE_SHAPE:LAYER]
[TISSUE_LAYER:BY_CATEGORY:ALL:SLADE]
[PHYS_ATT_RANGE:STRENGTH:5000:5000:5000:5000:5000:5000:5000]
[PHYS_ATT_RANGE:TOUGHNESS:5000:5000:5000:5000:5000:5000:5000]
[PHYS_ATT_RANGE:AGILITY:5000:5000:5000:5000:5000:5000:5000]
[PHYS_ATT_RANGE:RECUPERATION:5000:5000:5000:5000:5000:5000:5000]
[NATURAL_SKILL:DODGING:25]
[NATURAL_SKILL:GRASP_STRIKE:25]
[SPEED:100]
[BODY_SIZE:0:0:90]
[ALL_ACTIVE]
[NOBREATHE][NO_FEVERS][NOSTUN][NONAUSEA][NOEMOTION]
[NOEXERT][NOFEAR]
[NOMEAT]
[NOSTUCKINS]
[PARALYZEIMMUNE]
[EXTRAVISION]
[FIREIMMUNE]
[NO_EAT]
[NO_DRINK]
[NO_SLEEP]
[NO_DIZZINESS]
[CANNOT_UNDEAD]
[AMPHIBIOUS]
[FLIER]
[SWIMS_INNATE][SWIM_SPEED:100]
[ITEMCORPSE:STONE:NO_SUBTYPE:STONE:SLADE]
[ATTACK:SLAM:BODYPART:BY_TYPE:UPPERBODY]
[ATTACK_SKILL:GRASP_STRIKE]
[ATTACK_VERB:slam into:slams into]
[ATTACK_CONTACT_PERC:100]
[ATTACK_FLAG_WITH]
[ATTACK_PRIORITY:MAIN]
Or, for even less survivability, now with clouds of burning, poisonous brimstone:
[CREATURE:SLADE_PEBBLE]
[DESCRIPTION:An animate, burning stone chipped from the bedrock of Hell itself. Beware its fiery brimstone! Now you will know why mining slade is forbidden.]
[NAME:slade pebble:slade pebbles:slade pebble]
[CASTE_NAME:slade pebble:slade pebbles:slade pebble]
[CREATURE_TILE:'.'][COLOR:0:0:1]
[BIOME:SUBTERRANEAN_CHASM]
[UNDERGROUND_DEPTH:5:5][POPULATION_NUMBER:1:1][CLUSTER_NUMBER:1:1][FREQUENCY:75]
[LIKES_FIGHTING]
[LARGE_PREDATOR]
[NOBONES]
[NO_GENDER]
[BUILDINGDESTROYER:2]
[PREFSTRING:density]
[BODY:BASIC_1PARTBODY_THOUGHT]
[NO_THOUGHT_CENTER_FOR_MOVEMENT]
[SPHERE:DEATH]
[EVIL]
[HOMEOTHERM:20500]
[TISSUE:SLADE]
[TISSUE_NAME:slade:NP]
[TISSUE_MATERIAL:INORGANIC:SLADE]
[MUSCULAR]
[FUNCTIONAL]
[STRUCTURAL]
[RELATIVE_THICKNESS:1]
[CONNECTS]
[TISSUE_SHAPE:LAYER]
[TISSUE_LAYER:BY_CATEGORY:ALL:SLADE]
[PHYS_ATT_RANGE:STRENGTH:5000:5000:5000:5000:5000:5000:5000]
[PHYS_ATT_RANGE:TOUGHNESS:5000:5000:5000:5000:5000:5000:5000]
[PHYS_ATT_RANGE:AGILITY:5000:5000:5000:5000:5000:5000:5000]
[PHYS_ATT_RANGE:RECUPERATION:5000:5000:5000:5000:5000:5000:5000]
[NATURAL_SKILL:DODGING:25]
[NATURAL_SKILL:GRASP_STRIKE:25]
[SPEED:100]
[BODY_SIZE:0:0:90]
[ALL_ACTIVE]
[NOBREATHE][NO_FEVERS][NOSTUN][NONAUSEA][NOEMOTION]
[NOEXERT][NOFEAR]
[NOMEAT]
[NOSTUCKINS]
[PARALYZEIMMUNE]
[EXTRAVISION]
[FIREIMMUNE]
[NO_EAT]
[NO_DRINK]
[NO_SLEEP]
[NO_DIZZINESS]
[CANNOT_UNDEAD]
[AMPHIBIOUS]
[FLIER]
[SWIMS_INNATE][SWIM_SPEED:100]
[ITEMCORPSE:STONE:NO_SUBTYPE:STONE:SLADE]
[ATTACK:SLAM:BODYPART:BY_TYPE:UPPERBODY]
[ATTACK_SKILL:GRASP_STRIKE]
[ATTACK_VERB:slam into:slams into]
[ATTACK_CONTACT_PERC:100]
[ATTACK_FLAG_WITH]
[ATTACK_PRIORITY:MAIN]
[USE_MATERIAL_TEMPLATE:FIERY_BRIMSTONE_1:STONE_TEMPLATE]
[STATE_NAME:ALL_SOLID:fiery brimstone]
[STATE_ADJ:ALL_SOLID:fiery brimstone]
[STATE_NAME:LIQUID:molten brimstone]
[STATE_ADJ:LIQUID:molten brimstone]
[STATE_NAME:GAS:burning brimstone gas]
[STATE_ADJ:GAS:burning brimstone gas]
[PREFIX:NONE]
[MAT_FIXED_TEMP:20500]
[IGNITE_POINT:12500]
[BOILING_POINT:20499]
[SYNDROME]
[SYN_NAME:brimstone poisoning]
[SYN_AFFECTED_CLASS:GENERAL_POISON]
[SYN_IMMUNE_CREATURE:SLADE_PEBBLE:ALL]
[SYN_INHALED]
[CE_NAUSEA:SEV:130:PROB:95:RESISTABLE:SIZE_DILUTES:START:5:PEAK:10:END:70]
[CE_IMPAIR_FUNCTION:SEV:150:PROB:85:RESISTABLE:BP:BY_CATEGORY:LUNG:ALL:SIZE_DILUTES:START:30:PEAK:40:END:70]
[USE_MATERIAL_TEMPLATE:FIERY_BRIMSTONE_2:STONE_TEMPLATE]
[STATE_NAME:ALL_SOLID:fiery brimstone]
[STATE_ADJ:ALL_SOLID:fiery brimstone]
[STATE_NAME:LIQUID:molten brimstone]
[STATE_ADJ:LIQUID:molten brimstone]
[STATE_NAME:GAS:burning brimstone gas]
[STATE_ADJ:GAS:burning brimstone gas]
[PREFIX:NONE]
[MAT_FIXED_TEMP:20500]
[IGNITE_POINT:12500]
[MELTING_POINT:20499]
[BOILING_POINT:20501]
[SYNDROME]
[SYN_NAME:brimstone poisoning]
[SYN_AFFECTED_CLASS:GENERAL_POISON]
[SYN_IMMUNE_CREATURE:SLADE_PEBBLE:ALL]
[SYN_CONTACT]
[CE_PAIN:SEV:150:PROB:100:RESISTABLE:LOCALIZED:START:10:PEAK:50:END:100]
[MATERIAL_BREATH_ATTACK:LOCAL_CREATURE_MAT:FIERY_BRIMSTONE_2:TRAILING_DUST_FLOW]
[MATERIAL_BREATH_ATTACK:LOCAL_CREATURE_MAT:FIERY_BRIMSTONE_1:UNDIRECTED_DUST]
Watching one tear through squads of high master warriors in adamantine was deeply amusing.