node tools/spawn.js --write writes tools/spawn-tyranids.json, one entry per ledger form that puts units or models into play (88 of the ledger's forms), from the rules in tools/spawn-rules.json (our numbers, each citing a Wahapedia 11th-edition page or the BSData catalogue at 374f505; no rules wording). The ledger (T-596) reads it; nothing here changes the ledger, the page or the live site.
Method
- Found by: walking BSData's Tyranids.json and Library - Tyranids.json for abilities that add a new unit or bring destroyed models back (Biovores, Harpy, Sporocyst, Tervigon, Parasite of Mortrex), then Wahapedia's Tyranids faction page for detachment rules and stratagems that do the same (Feed the Swarm; three stratagems, not counted, below). The ledger's own rule list agrees: its "Adds units or models" and "Heals or returns models" rules are these plus heals that place nothing (Unstoppable Monster, Swallow Whole).
- A turn is a battle round (one of the army's turns and one of the enemy's): every rule here fires at most once a round, the Harpy's in the enemy's turn.
- Points placed per round = expected models × their worth. A new unit is priced at its own size on its cost table (below the smallest size at the smallest size's points per model; the mean over the dice when the count is rolled). Returned models are priced at the receiving unit's points per model at its smallest size (Termagants 6.0). The spawned copies (Spore Mines (Biovore), Mucolid Spores (Sporocyst), Ripper Swarms (Parasite of Mortrex)) have no points of their own, so each is priced as its stand-alone datasheet.
- Per 100 = points per round ÷ the form's points × 100 (the round the rule can fire).
- First three rounds = per 100 × the mean of the rule's availability in rounds 1, 2 and 3, averaged over going first and second.
- Bodies (Jordan, 3 Oct): besides points, each line gives the new units placed per round per 100 points (
spawnUnitsPer100,first3UnitsPer100), the placed models' OC (spawnOC,spawnOCPer100), whether a placed unit can do an action (spawnCanAction) or hold an objective (spawnCanControl), whether it counts for the deck's unit-count secondaries (spawnPresence) and where it can be set up (spawnPlacement). - Left to the ledger: how much a placed point is worth (Spore Mines blow up); what is given up to spawn (
instead: the Biovores' and Sporocyst's shooting, the Harpy's mortal wounds); melee landing for the Parasite (gate); the army-wide once-a-turn limit (armyOncePerTurn: a second Biovore unit adds nothing).
What a spawned body can do (11th-edition core rules and the 2026-27 mission deck)
- No actions from OC 0. A unit with OC 0 cannot start an action (core rules 16). Spore Mines, Mucolid Spores and the Parasite's Ripper Swarms are all OC 0 (BSData), so none of them can do an action, and none can hold an objective (14.02: only OC 1 or more counts). Jordan's "free units that do actions" does not hold in 11th edition.
- They do count as bodies. The deck's unit-count secondaries leave out only AIRCRAFT and Battle-shocked units, so an OC 0 unit counts: Engage on All Fronts (table quarters), Behind Enemy Lines (the enemy's zone), Display of Might (No Man's Land), Outflank (battlefield edges), Centre Ground (the centre). This, plus screening and blocking, is where a spawned unit earns its keep, and the Biovores' 48" reach puts the mine almost anywhere more than 8" from the enemy. The ledger should credit
spawnUnitsPer100withspawnPresenceto a presence line rather than to Actions. - Returned models (Tervigon, Feed the Swarm) make no new unit but add OC: Termagants are OC 2 a model, so they count for Score through
spawnOCPer100.
Every spawning unit
| Form | Rule | Placed per round | Pts / 100 | First 3 | Units / 100 | First 3 | OC / 100 | Notes |
|---|---|---|---|---|---|---|---|---|
| Biovores ×1 (60) | Seed Spore Mines | 1 Spore Mine, 18.3 pts | 30.6 | 30.6 | 1.67 | 1.67 | 0 | in place of shooting; army once a turn |
| Biovores ×2 (100) | 2 Spore Mines, 36.7 pts | 36.7 | 36.7 | 1.00 | 1.00 | 0 | ||
| Biovores ×3 (140) | 3 Spore Mines, 55 pts | 39.3 | 39.3 | 0.71 | 0.71 | 0 | ||
| Sporocyst (145) | Seed Mucolids | 1 Mucolid Spore, 30 pts | 20.7 | 20.7 | 0.69 | 0.69 | 0 | within 18"; in place of shooting; army once a turn |
| Harpy (185) | Spore Mine Cysts | D3 Spore Mines, 36.7 pts | 19.8 | 9.9 | 0.54 | 0.27 | 0 | in place of 4 mortal wounds; rounds 0, 0.5, 1 |
| Parasite of Mortrex (70) | Parasitic Infection | 0.21 kills × D3 Rippers (40 pts) = 8.3 pts | 11.8 | 7.9 | 0.30 | 0.20 | 0 | needs its melee to land (gate); rounds 0, 1, 1 |
| Tervigon (160) | Spawn Termagants | 5 Termagants back, 30 pts | 18.8 | 15.6 | 0 | 0 | 6.25 | needs destroyed Termagants; rounds 0.5, 1, 1 |
| Pyrovores ×1 / ×2 / ×3 (40 / 70 / 100) | Feed the Swarm | 3 Termagants back, 18 pts | 45 / 25.7 / 18 | 37.5 / 21.4 / 15 | 0 | 0 | 15 / 8.6 / 6 | Assimilation Swarm only |
| Ripper Swarms ×1 / ×2 / ×3 (30 / 40 / 50) | Feed the Swarm | 3 Termagants back, 18 pts | 60 / 45 / 36 | 50 / 37.5 / 30 | 0 | 0 | 20 / 15 / 12 | Assimilation Swarm only |
| Psychophage (110) | Feed the Swarm | 18 pts | 16.4 | 13.6 | 0 | 0 | 5.45 | Assimilation Swarm only |
| Haruspex (125) | Feed the Swarm | 18 pts | 14.4 | 12 | 0 | 0 | 4.8 | Assimilation Swarm only |
| Norn Assimilator (250) | Feed the Swarm | 18 pts | 7.2 | 6 | 0 | 0 | 2.4 | Assimilation Swarm only |
Every other Tyranid form places nothing (0); no joined form has a spawning member.
The Parasite's kills: the barbed ovipositor (one attack, WS 2+, S3, AP −2, D3, anti-infantry 3+) slays a fresh model of the GEQ stand-in 0.556 of the time, MEQ 0.247 (the D3 must roll 2 or more), TEQ 0.093 (a 3, and the 4+ invulnerable save); weighted by the typical army's chaff (95 pts), elite infantry (269) and heavy infantry (383): 0.207 kills a fight.
Not counted
- Stratagems that bring models or units back: Endless Swarm (Invasion Fleet, up to D3+3 models to one or two ENDLESS MULTITUDE units), Unending Waves (Unending Swarm, once a battle, a destroyed ENDLESS MULTITUDE unit again in reserves), Replenishing Swarms (Subterranean Assault, up to D3+1 one-wound models near a tunnel). They cost command points and belong to no unit; the CP card (T-558) prices stratagems.
- The Mortrexite Implant (a Crusade relic) and the heals that place no model.
Uncertain
- Returns need losses. The Tervigon and Feed the Swarm only bring back models already destroyed. The numbers assume enough losses from the army's second Command phase on (round 1 at 0.5: only when going second). A Termagant unit near a Tervigon may not have lost five models every round.
- Feed the Swarm priced on Termagants. Three Termagants (18 pts) is the reference; three Gargoyles would be 24, three Hormagaunts 21, three Neurogaunts 12.3, and a single returned infantry model of a non-ENDLESS MULTITUDE unit (one Tyranid Warrior, say) may be worth more. The heal choice (D3+1 wounds on one model) is not counted. A cheap Harvester's 45 to 60 per 100 is the rule's real reach, but only while a damaged ENDLESS MULTITUDE unit stands within 6".
- Returned models priced at the smallest size (Termagants 6.0 a model; 5.5 in a unit of 20).
- The Parasite's kills are against a fresh model. Its clawed limbs, resolved first, often leave a wounded model, which the ovipositor then kills on any damage roll: against a wounded front model the chance is 0.556 (GEQ), 0.370 (MEQ), 0.278 (TEQ), 0.35 weighted, so 14 pts a fight (20 per 100). It is also assumed to fight infantry; the share of infantry in the typical army is 747 of 2,000 points. Detachment buffs to its attacks are not counted.
- Biovores at full strength. The mine count follows the models left in the unit.
- The Harpy's rounds follow the AIRCRAFT rules: in reserves at the start, on the table only after its own turn's arrival, back to reserves at the end of the enemy's turn.