I made some bigger hydras. The dodecahydron boasts 12 heads and is slightly bigger than the hydra. The isocahydra has 20 heads and is even bigger still. One isocahydra can kill hundreds of kobolds!
Unfortunately, they still can't kill dragons or bronze colossuses.
[CREATURE:DODECAHYDRA]
[DESCRIPTION:A giant dragon-like monster with twelve biting heads.]
[NAME:dodecahydra:dodecahydras:dodecahydra]
[CASTE_NAME:dodecahydra:dodecahydras:dodecahydra]
[CREATURE_TILE:'H'][COLOR:4:0:0]
[PETVALUE:11000]
[PET_EXOTIC]
[BIOME:ANY_LAND]
[FREQUENCY:5]
[FANCIFUL]
[MEGABEAST][DIFFICULTY:12]
[ATTACK_TRIGGER:90:12000:120000]
[SPHERE:MUCK]
[SPHERE:REBIRTH]
[SPHERE:STRENGTH]
[NOFEAR][NOEXERT]
[NOSTUN]
[NOPAIN]
[BUILDINGDESTROYER:2]
[LIKES_FIGHTING]
[GRASSTRAMPLE:60]
[BONECARN]
[PREFSTRING:twelve heads]
[BODY:BASIC_2PARTBODY:12HEADNECKS:BASIC_FRONTLEGS:BASIC_REARLEGS:TAIL:2EYES:NOSE:2LUNGS:HEART:GUTS:ORGANS:THROAT:SPINE:BRAIN:SKULL:3TO
ES_FQ:3TOES_RQ:MOUTH:GENERIC_TEETH_WITH_FANGS:RIBCAGE]
[BODY_DETAIL_PLAN:STANDARD_MATERIALS]
[REMOVE_MATERIAL:SKIN]
[REMOVE_MATERIAL:LEATHER]
[REMOVE_MATERIAL:HAIR]
[USE_MATERIAL_TEMPLATE:SCALE:SCALE_TEMPLATE]
[BODY_DETAIL_PLAN:STANDARD_TISSUES]
[REMOVE_TISSUE:SKIN]
[REMOVE_TISSUE:HAIR]
[USE_TISSUE_TEMPLATE:SCALE:SCALE_TEMPLATE]
[BODY_DETAIL_PLAN:VERTEBRATE_TISSUE_LAYERS:SCALE:FAT:MUSCLE:BONE:CARTILAGE]
[USE_MATERIAL_TEMPLATE:CLAW:NAIL_TEMPLATE]
[USE_TISSUE_TEMPLATE:CLAW:CLAW_TEMPLATE]
[TISSUE_LAYER:BY_CATEGORY:TOE:CLAW:FRONT]
[SELECT_TISSUE_LAYER:HEART:BY_CATEGORY:HEART]
[TL_MAJOR_ARTERIES]
[BODY_DETAIL_PLAN:STANDARD_HEAD_POSITIONS]
[BODY_DETAIL_PLAN:HUMANOID_RIBCAGE_POSITIONS]
[USE_MATERIAL_TEMPLATE:SINEW:SINEW_TEMPLATE]
[TENDONS:LOCAL_CREATURE_MAT:SINEW:1]
[LIGAMENTS:LOCAL_CREATURE_MAT:SINEW:1]
[HAS_NERVES]
[USE_MATERIAL_TEMPLATE:BLOOD:BLOOD_TEMPLATE]
[BLOOD:LOCAL_CREATURE_MAT:BLOOD:LIQUID]
[CREATURE_CLASS:GENERAL_POISON]
[GETS_WOUND_INFECTIONS]
[GETS_INFECTIONS_FROM_ROT]
[USE_MATERIAL_TEMPLATE:PUS:PUS_TEMPLATE]
[PUS:LOCAL_CREATURE_MAT:PUS:LIQUID]
[BODY_SIZE:0:0:250000]
[BODY_SIZE:20:0:10000000]
[BODY_APPEARANCE_MODIFIER:LENGTH:90:95:98:100:102:105:110]
[BODY_APPEARANCE_MODIFIER:HEIGHT:90:95:98:100:102:105:110]
[BODY_APPEARANCE_MODIFIER:BROADNESS:90:95:98:100:102:105:110]
[ATTACK:BITE:CHILD_BODYPART_GROUP:BY_CATEGORY:HEAD:BY_CATEGORY:TOOTH]
[ATTACK_SKILL:BITE]
[ATTACK_VERB:bite:bites]
[ATTACK_CONTACT_PERC:100]
[ATTACK_PENETRATION_PERC:100]
[ATTACK_FLAG_EDGE]
[ATTACK_PRIORITY:MAIN]
[ATTACK_FLAG_CANLATCH]
[ALL_ACTIVE]
[LAIR:SIMPLE_BURROW:100]
[LAIR_HUNTER]
[NATURAL_SKILL:BITE:8]
[NATURAL_SKILL:GRASP_STRIKE:8]
[NATURAL_SKILL:STANCE_STRIKE:8]
[NATURAL_SKILL:MELEE_COMBAT:8]
[NATURAL_SKILL:DODGING:8]
[NATURAL_SKILL:SITUATIONAL_AWARENESS:15]
[SWIMS_INNATE][SWIM_SPEED:2500]
[HOMEOTHERM:10040]
[CASTE:FEMALE]
[FEMALE]
[CASTE:MALE]
[MALE]
[SELECT_CASTE:ALL]
[SET_TL_GROUP:BY_CATEGORY:ALL:SCALE]
[TL_COLOR_MODIFIER:GOLD:1:RED:1]
[TLCM_NOUN:scales:PLURAL]
[SET_TL_GROUP:BY_CATEGORY:EYE:EYE]
[TL_COLOR_MODIFIER:BLACK:1]
[TLCM_NOUN:eyes:PLURAL]
[SELECT_MATERIAL:ALL]
[MULTIPLY_VALUE:12]
[SELECT_TISSUE_LAYER:ALL]
[TL_HEALING_RATE:1]
[CREATURE:ISOCAHYDRA]
[DESCRIPTION:A giant dragon-like monster with twenty biting heads.]
[NAME:isocahydra:isocahydras:isocahydra]
[CASTE_NAME:isocahydra:isocahydras:isocahydra]
[CREATURE_TILE:'H'][COLOR:5:0:1]
[PETVALUE:12000]
[PET_EXOTIC]
[BIOME:ANY_LAND]
[FREQUENCY:5]
[FANCIFUL]
[MEGABEAST][DIFFICULTY:14]
[ATTACK_TRIGGER:100:12500:125000]
[SPHERE:MUCK]
[SPHERE:REBIRTH]
[SPHERE:STRENGTH]
[NOFEAR][NOEXERT]
[NOSTUN]
[NOPAIN]
[BUILDINGDESTROYER:2]
[LIKES_FIGHTING]
[GRASSTRAMPLE:80]
[BONECARN]
[PREFSTRING:twenty heads]
[BODY:BASIC_2PARTBODY:20HEADNECKS:BASIC_FRONTLEGS:BASIC_REARLEGS:TAIL:2EYES:NOSE:2LUNGS:HEART:GUTS:ORGANS:THROAT:SPINE:BRAIN:SKULL:3TO
ES_FQ:3TOES_RQ:MOUTH:GENERIC_TEETH_WITH_FANGS:RIBCAGE]
[BODY_DETAIL_PLAN:STANDARD_MATERIALS]
[REMOVE_MATERIAL:SKIN]
[REMOVE_MATERIAL:LEATHER]
[REMOVE_MATERIAL:HAIR]
[USE_MATERIAL_TEMPLATE:SCALE:SCALE_TEMPLATE]
[BODY_DETAIL_PLAN:STANDARD_TISSUES]
[REMOVE_TISSUE:SKIN]
[REMOVE_TISSUE:HAIR]
[USE_TISSUE_TEMPLATE:SCALE:SCALE_TEMPLATE]
[BODY_DETAIL_PLAN:VERTEBRATE_TISSUE_LAYERS:SCALE:FAT:MUSCLE:BONE:CARTILAGE]
[USE_MATERIAL_TEMPLATE:CLAW:NAIL_TEMPLATE]
[USE_TISSUE_TEMPLATE:CLAW:CLAW_TEMPLATE]
[TISSUE_LAYER:BY_CATEGORY:TOE:CLAW:FRONT]
[SELECT_TISSUE_LAYER:HEART:BY_CATEGORY:HEART]
[TL_MAJOR_ARTERIES]
[BODY_DETAIL_PLAN:STANDARD_HEAD_POSITIONS]
[BODY_DETAIL_PLAN:HUMANOID_RIBCAGE_POSITIONS]
[USE_MATERIAL_TEMPLATE:SINEW:SINEW_TEMPLATE]
[TENDONS:LOCAL_CREATURE_MAT:SINEW:1]
[LIGAMENTS:LOCAL_CREATURE_MAT:SINEW:1]
[HAS_NERVES]
[USE_MATERIAL_TEMPLATE:BLOOD:BLOOD_TEMPLATE]
[BLOOD:LOCAL_CREATURE_MAT:BLOOD:LIQUID]
[CREATURE_CLASS:GENERAL_POISON]
[GETS_WOUND_INFECTIONS]
[GETS_INFECTIONS_FROM_ROT]
[USE_MATERIAL_TEMPLATE:PUS:PUS_TEMPLATE]
[PUS:LOCAL_CREATURE_MAT:PUS:LIQUID]
[BODY_SIZE:0:0:300000]
[BODY_SIZE:20:0:12000000]
[BODY_APPEARANCE_MODIFIER:LENGTH:90:95:98:100:102:105:110]
[BODY_APPEARANCE_MODIFIER:HEIGHT:90:95:98:100:102:105:110]
[BODY_APPEARANCE_MODIFIER:BROADNESS:90:95:98:100:102:105:110]
[ATTACK:BITE:CHILD_BODYPART_GROUP:BY_CATEGORY:HEAD:BY_CATEGORY:TOOTH]
[ATTACK_SKILL:BITE]
[ATTACK_VERB:bite:bites]
[ATTACK_CONTACT_PERC:100]
[ATTACK_PENETRATION_PERC:100]
[ATTACK_FLAG_EDGE]
[ATTACK_PRIORITY:MAIN]
[ATTACK_FLAG_CANLATCH]
[ALL_ACTIVE]
[LAIR:SIMPLE_BURROW:100]
[LAIR_HUNTER]
[NATURAL_SKILL:BITE:12]
[NATURAL_SKILL:GRASP_STRIKE:12]
[NATURAL_SKILL:STANCE_STRIKE:12]
[NATURAL_SKILL:MELEE_COMBAT:12]
[NATURAL_SKILL:DODGING:12]
[NATURAL_SKILL:SITUATIONAL_AWARENESS:15]
[SWIMS_INNATE][SWIM_SPEED:2500]
[HOMEOTHERM:10040]
[CASTE:FEMALE]
[FEMALE]
[CASTE:MALE]
[MALE]
[SELECT_CASTE:ALL]
[SET_TL_GROUP:BY_CATEGORY:ALL:SCALE]
[TL_COLOR_MODIFIER:GOLD:1:RED:1]
[TLCM_NOUN:scales:PLURAL]
[SET_TL_GROUP:BY_CATEGORY:EYE:EYE]
[TL_COLOR_MODIFIER:BLACK:1]
[TLCM_NOUN:eyes:PLURAL]
[SELECT_MATERIAL:ALL]
[MULTIPLY_VALUE:15]
[SELECT_TISSUE_LAYER:ALL]
[TL_HEALING_RATE:1]
Next up: more poisonous blood