Sorry, I mis-read some of the early posts. I thought the emphasis was on the silliness rather than the playability. As is, a map with tribbles is fundamentally unplayable.
It was fairly simple to dial down the difficulty (reduce the number of tribblets to one, lengthen the time before activating them, remove the vermin tag) so that they are merely a ticking time bomb rather than an insta-kill. That also required fixing a small bug in how the "rouse tribble" interaction worked. (They still don't have blood because I haven't been able to track down why some were randomly bleeding to death during the birthing and rousing cycle. This doesn't really impact how hard they are to kill.)
Still not going to offend me if you don't include them, but I think this addresses the concerns raised, especially if they appear entombed in rock.
creature_tribble
[OBJECT:CREATURE]
[CREATURE:TRIBBLE]
[DESCRIPTION:A harmless creature, I assure you.]
[NAME:tribble:tribbles:tribble]
[CREATURE_TILE:249][COLOR:6:0:0]
[PETVALUE:10][NO_GENDER][FREQUENCY:100]
[GNAWER:gnawed]
[SMALL_REMAINS][NATURAL][PET]
[NOT_BUTCHERABLE]
[BIOME:NOT_FREEZING]
[POPULATION_NUMBER:2500:5000]
[TRIGGERABLE_GROUP:5:50]
[PREFSTRING:purring]
[PREFSTRING:softness]
[PREFSTRING:furriness]
[PREFSTRING:effect on FPS]
[CASTE:REPRODUCER]
[CASTE_NAME:tribble:tribbles:tribble]
[CASTE:TRIBBLET]
[CASTE_NAME:tribblet:tribblets:tribblet]
[SELECT_CASTE:ALL]
[BODY:BASIC_1PARTBODY_THOUGHT:MULTISPAWN]
[BODY_DETAIL_PLAN:STANDARD_MATERIALS]
[BODY_DETAIL_PLAN:STANDARD_TISSUES]
[BODY_DETAIL_PLAN:VERTEBRATE_TISSUE_LAYERS:SKIN:FAT:MUSCLE:BONE:CARTILAGE]
[BODY_DETAIL_PLAN:BODY_HAIR_TISSUE_LAYERS:HAIR]
[SELECT_TISSUE_LAYER:HEART:BY_CATEGORY:HEART]
[TL_MAJOR_ARTERIES]
[BODY_DETAIL_PLAN:STANDARD_HEAD_POSITIONS]
[USE_MATERIAL_TEMPLATE:SINEW:SINEW_TEMPLATE]
[TENDONS:LOCAL_CREATURE_MAT:SINEW:200]
[LIGAMENTS:LOCAL_CREATURE_MAT:SINEW:200]
[HAS_NERVES]
[CREATURE_CLASS:GENERAL_POISON]
[GETS_WOUND_INFECTIONS]
[GETS_INFECTIONS_FROM_ROT]
[BODY_SIZE:0:0:250]
[BODY_APPEARANCE_MODIFIER:BROADNESS:90:95:98:100:102:105:110]
[MAXAGE:2:4]
[ALL_ACTIVE]
[HAS_NERVES]
[USE_MATERIAL_TEMPLATE:MELTAWAY:BLOOD_TEMPLATE]
[STATE_COLOR:ALL_SOLID:WHITE]
[STATE_NAME_ADJ:ALL_SOLID:frozen stuff]
[STATE_COLOR:LIQUID:WHITE]
[STATE_NAME_ADJ:LIQUID:stuff]
[STATE_COLOR:GAS:WHITE]
[STATE_NAME_ADJ:GAS:boiling stuff]
[DISPLAY_COLOR:7:0:1]
[MATERIAL_VALUE:1]
[SPEC_HEAT:4181]
[IGNITE_POINT:NONE]
[MELTING_POINT:9800]
[BOILING_POINT:9910]
[HEATDAM_POINT:9900]
[COLDDAM_POINT:NONE]
[MAT_FIXED_TEMP:10000]
[SOLID_DENSITY:1200]
[LIQUID_DENSITY:1200]
[MOLAR_MASS:20000]
[IMPACT_YIELD:10000]
[IMPACT_FRACTURE:10000]
[IMPACT_STRAIN_AT_YIELD:100]
[COMPRESSIVE_YIELD:10000]
[COMPRESSIVE_FRACTURE:10000]
[COMPRESSIVE_STRAIN_AT_YIELD:100]
[TENSILE_YIELD:10000]
[TENSILE_FRACTURE:10000]
[TENSILE_STRAIN_AT_YIELD:100]
[TORSION_YIELD:10000]
[TORSION_FRACTURE:10000]
[TORSION_STRAIN_AT_YIELD:100]
[SHEAR_YIELD:6600]
[SHEAR_FRACTURE:6600]
[SHEAR_STRAIN_AT_YIELD:100]
[BENDING_YIELD:10000]
[BENDING_FRACTURE:10000]
[BENDING_STRAIN_AT_YIELD:100]
[MAX_EDGE:500]
[ABSORPTION:100]
[LIQUID_MISC_CREATURE]
[ROTS]
[TISSUE:MELTAWAY]
[TISSUE_NAME:stuff:NP]
[TISSUE_MATERIAL:LOCAL_CREATURE_MAT:MELTAWAY]
[MUSCULAR]
[FUNCTIONAL]
[STRUCTURAL]
[RELATIVE_THICKNESS:1]
[CONNECTS]
[TISSUE_SHAPE:LAYER]
[USE_MATERIAL_TEMPLATE:PUS:PUS_TEMPLATE]
[PUS:LOCAL_CREATURE_MAT:PUS:LIQUID]
[HOMEOTHERM:10070]
[SWIMS_INNATE][SWIM_SPEED:2000]
[SET_BP_GROUP:BY_TOKEN:OVIPOSITOR]
[TISSUE_LAYER:BY_CATEGORY:DROPPER:MELTAWAY]
[CAN_DO_INTERACTION:BIRTH_TRIBBLE]
[CDI:FREE_ACTION]
[CDI:WAIT_PERIOD:100]
[CAN_DO_INTERACTION:ROUSE_TRIBBLE]
[CDI:FREE_ACTION]
[CDI:WAIT_PERIOD:200]
body_tribble
[OBJECT:BODY]
[BODY:MULTISPAWN]
[BP:OVIPOSITOR:reproductive organ:STP][CON:UB][CATEGORY:DROPPER][DEFAULT_RELSIZE:10]
[BP:GERM:tribblet:STP][CON:OVIPOSITOR][GRASP][CATEGORY:BODY][DEFAULT_RELSIZE:500]
interaction_tribble
[OBJECT:INTERACTION]
[INTERACTION:ROUSE_TRIBBLE]
[I_SOURCE:CREATURE_ACTION]
[I_TARGET:A:CORPSE]
[IT_LOCATION:CONTEXT_ITEM]
[IT_AFFECTED_CREATURE:TRIBBLE:TRIBBLET]
[IT_CANNOT_HAVE_SYNDROME_CLASS:ROUSED_TRIBBLE]
[IT_MANUAL_INPUT:tribblet]
[I_EFFECT:RESURRECT]
[IE_TARGET:A]
[IE_IMMEDIATE]
[SYNDROME]
[SYN_NAME:rousing tribble]
[SYN_CLASS:ROUSED_TRIBBLE]
[CE_BODY_TRANSFORMATION:START:200]
[CE:CREATURE:TRIBBLE:REPRODUCER]
[INTERACTION:BIRTH_TRIBBLE]
[I_SOURCE:CREATURE_ACTION]
[I_TARGET:A:CORPSE]
[IT_LOCATION:CONTEXT_ITEM]
[IT_MANUAL_INPUT:tribblet]
[IT_AFFECTED_CREATURE:TRIBBLE:ALL]
[IT_REQUIRES:FIT_FOR_ANIMATION]
[I_EFFECT:ANIMATE]
[IE_TARGET:A]
[IE_IMMEDIATE]
[SYNDROME]
[SYN_NAME:birthing tribble]
[CE_BODY_TRANSFORMATION:START:0]
[CE:CREATURE:TRIBBLE:TRIBBLET]
Edit: typo.