Cobblemon Dynamic Spawns

Read this in Português (Brasil).

An addon for Cobblemon 1.7.3 (Minecraft 1.21.1, Fabric) that makes Pokémon spawning far more dynamic: wider biome variety, light-based cave spawns, wild hordes led by evolved leaders, SV-style Mass Outbreaks, and a dash of pure randomness.

Current version: 1.1.0 — see the changelog.

Features

1. Biome + light-based spawn variety (datapack)

A purely additive layer on top of Cobblemon's default spawn pool — nothing from the original spawns is modified, we only add new entries under data/cobblemon/spawn_pool_world/dynamicspawns_*.json:

Dark caves (light 0-3, no sky access): Zubat, Gastly, Sableye (rare)
Lit caves (light 4+, no sky access): Geodude, Machop, Aron, Roggenrola
Forests: Hoothoot (night), Seedot, Shroomish, Pineco
Plains: Ponyta, Doduo, Growlithe, Eevee (rare)
Deserts: Sandshrew, Trapinch (day), Cacnea (night), Sandile
Snowy biomes: Swinub, Snorunt (night), Cubchoo, Snover
Coasts/beaches: Krabby, Wingull (day), Corphish, Staryu (night)

2. Hordes

When a base species that can evolve spawns naturally (e.g. Bidoof), there is a configurable chance (default 10%) that it turns into a horde:

The spawned Pokémon becomes one of the horde members
An evolved leader (e.g. Bibarel) spawns nearby with a level bonus (+5) and 3 random perfect IVs
3-5 more base members spawn around it

Triggering on the common base-stage spawns (rather than the rare evolved ones) makes hordes far more frequent — with the trigger applied to most natural spawns, a chance as low as a few percent already produces plenty; tune chance down accordingly.

3. Mass Outbreaks (Scarlet/Violet style)

At random intervals (measured in in-game day time — so sleeping/advancing days brings them, not just real playtime), a global outbreak starts somewhere in the world, announced in chat to every player:

Up to 6 simultaneous outbreaks (maxSimultaneous), each with a different species, with staggered start times
Territorial spacing: active outbreaks stay at least 16 chunks (256 blocks) apart (minChunkDistanceBetweenOutbreaks) — they never overlap; if no valid position exists, the start is postponed to the next interval
The first outbreak is guaranteed the moment the first in-game day ends (startAfterInGameDays); subsequent ones follow the random interval. Admin commands bypass this rule
A single species mass-spawning (budget of 80 Pokémon, max 8 alive per outbreak)
Legendary, mythical and ultra-beast species never become outbreaks (excludedLabels)
Pokémon only materialize while a player is within the outbreak's activation radius (activationRadius), so they always spawn in loaded, ticking chunks — the outbreak is announced globally with coordinates; you travel there to trigger the spawns (Scarlet/Violet style)
Terrain-matched: the species is picked to fit the center (water dweller over ocean, land dweller on solid ground), and each individual spawn is re-checked — no fish on dry land or land Pokémon out in the ocean
Defeat/catch 30 → shiny rolls x2 | 60 → x3 (announced in chat)
Escalating levels: every clearsPerLevelStep (10) Pokémon defeated/caught, the next spawns gain +levelBonusPerStep (8) levels — the outbreak gets tougher as you thin it out (e.g. 15-40 → ~39-64 after 30 → ~63-80 after 60). Variation comes from the level range, capped at levelCap (80)
IV progression (SV-style): every clearsPerIvStep (20) Pokémon cleared, the next spawns gain +1 guaranteed perfect IV (31), from baseGuaranteedIvs up to maxProgressionIvs (4); the rest stay random
Shiny reward IVs: a shiny from the outbreak comes near-perfect — shinyMinPerfectIvs-shinyMaxPerfectIvs (5-6) guaranteed 31 IVs
Clear the entire outbreak → a guaranteed shiny spawns as the final reward
Ends when its lifetime runs out (also in-game day time, so advancing/sleeping ends outbreaks too) or when fully cleared
Awareness: joining the world lists any active outbreaks (coords + minutes left), and /dynamicspawns outbreak info shows each one's progress and time remaining
Persistent: active outbreaks and the schedule are saved per-world (dynamicspawns_outbreaks.json), so they survive closing and reopening the world instead of restarting. The lifetime uses world time (gameTime), so it counts down while the server runs — regardless of whether the outbreak's chunk is loaded — and pauses while the world is closed. Reopening a world no longer spawns a spurious outbreak

4. Flying spawns

Birds and other true fliers spawn in the air, already flying, instead of standing on the ground — an Altaria shows up gliding above the terrain rather than sitting in a field. A "true flier" is a species that flies and isn't aquatic: Cobblemon marks some water Pokémon (Dragonair, Dragonite, jellyfish, eels, squids) with canFly, and those are deliberately not raised into the sky. Height above the surface is configurable (minHeight/maxHeight, default 12-40; raise it toward ~120 for cloud-level spawns), and onlyPureFliers can limit it to species that can't walk. Uses Cobblemon's canFly/setFlying API — no mixins.

On top of that, a recurring sky spawner (skyFliers) periodically spawns a few fliers high in the air near each player, under open sky. The pool excludes aquatic fliers, legendaries/mythicals/ultra-beasts and very rare species (low catch rate), and the pick is weighted by Cobblemon's rarity buckets (bucketWeights, common>uncommon>rare>ultra-rare) so common fliers show up more than rare ones. By default it's strict pure fliers (species that can't walk, e.g. Zubat, Drifloon); set onlyPureFliers: false to also include walking birds like Altaria and Pidgeot. Interval, count, height, distance and levels are all configurable.

5. Random spawns

6% of natural spawns (configurable) are swapped for another species, ignoring biome rules — any Pokémon can show up anywhere, but following Cobblemon's own rarity:

The replacement is drawn by rarity bucket (read at runtime from the world spawn pool, so datapacks/modpacks are respected): first a bucket is rolled with the mod's weights (bucketWeights, default common 60 / uncommon 25 / rare 10 / ultra-rare 5 — softer than Cobblemon's 94.3/5/0.5/0.2 so rares show up more), then a uniform species within that bucket. A species' bucket is the most common one it appears in (e.g. Charizard = ultra-rare)
Species without any natural spawn (no bucket) can't be rolled
See docs/selecao-spawn-aleatorio.pdf for the full species listing with per-species probabilities
Legendaries, mythicals, ultra beasts, paradox forms and fossils are excluded from the roll (excludedLabels) — and natural spawns of those species are never swapped away (protects wild legendaries from modpacks)
In water/aquatic biomes (ocean, river, freshwater), the roll only picks species that actually live underwater (can breathe underwater)
Realistic levels (realisticLevels): the level scales with the species' base stat total, ±levelVariance (5) for spread — a Magikarp shows up around level 1-10 while a pseudo-legendary lands near 50-55 (rareLevelCap). Set realisticLevels: false to instead keep the original spawn's level
excludedNamespaces lets you exclude species from specific addons (e.g. lumymon)

BetterEnd / BetterNether integration

Optional datapack pools (activated only when the mods are installed, via neededInstalledMods) that give the modded dimensions a themed Pokémon roster:

BetterNether (22 biomes, 51 spawns): crimson/wart woods → Houndour, Salandit, Salazzle; warped woods → Gastly, Elgyem; fungi & upside-down forests → Koffing, Grimer, Weezing; swamplands → Croagunk, Stunky, Muk; magma & deltas → Slugma, Torkoal, Magcargo, plus Heatran as an ultra-rare; gravel desert → Geodude, Rhyhorn, Onix; bone reefs & soul plain → Cubone, Litwick, Duskull, Marowak, Spiritomb. No Grass/Water/Ice/Bug types, matching the Nether rules.
BetterEnd (25 biomes, 71 spawns): chorus forest → Elgyem, Drifblim; shadow forest & umbra valley → Murkrow, Zorua, Absol, Spiritomb; crystal/amber/ jade caves → Roggenrola, Carbink, Probopass, Beldum; glowing biomes → Clefairy, Ralts, Chimecho, plus Cresselia; dragon graveyards → Deino, Druddigon, Golurk, plus Regidrago; wastelands → Baltoy, Claydol, Rhydon; megalake → Chinchou, Frillish, Starmie, Lapras; ice starfield → Snorunt, Cryogonal, Avalugg, plus Deoxys; mushroomland & sulphur springs; end caves → Woobat, Noibat, Noivern.
Legendaries spawn only in the ultra-rare bucket at weight 0.05 (≈180× rarer than a common in the same biome).
Compat fix: BetterEnd's 25 biomes are added to the cobblemon:is_end tag (required: false), so Cobblemon's ~42 stock End spawns work there too — they otherwise appear not to, since nothing adds those biomes to minecraft:is_end.

Note these are native Cobblemon datapack spawns, independent of the mod's environment rules (which only govern the random-swap and outbreak systems).

Environmental rules

Both the random spawns and the outbreaks respect environmental sanity checks (config section environment), so Pokémon don't appear where they shouldn't:

Disabled dimensions (disabledDimensions, default minecraft:the_end): no dynamic randomness there — the End keeps its vanilla Pokémon
Banned types per dimension (dimensionBannedTypes, default: no Grass/ Water/Ice/Bug in the Nether): species with a banned type are filtered out for that dimension
Terrain suitability (enforceTerrain): water-dwelling species that avoid land only spawn in water (no more Relicanth on top of a tree), and water-averse species won't be placed submerged. Hordes skip aquatic species entirely since their members are placed on solid ground

Commands (permission level 2)

Command	Effect
`/dynamicspawns reload`	Reloads the config
`/dynamicspawns horde <species>`	Forces a horde at your position (use a base species that evolves, e.g. `bidoof`)
`/dynamicspawns outbreak start [species]`	Starts an outbreak (random, or of the given species near you)
`/dynamicspawns outbreak stop`	Ends all active outbreaks
`/dynamicspawns outbreak info`	Lists active outbreaks with status

Configuration

Generated at config/dynamicspawns.json on first run. Every number (chances, sizes, intervals, shiny milestones) is adjustable there; /dynamicspawns reload applies changes without restarting.

Cobbleverse compatibility

Verified against COBBLEVERSE 1.7.31 (Modrinth, April 2026): MC 1.21.1 + Fabric 0.18.4 + Cobblemon 1.7.3 + fabric-language-kotlin 1.13.10 — all dependencies match this mod. The pack's spawn-related addons (LumyMon, LegendaryMonuments, Raid Dens, Mega Showdown) use their own mechanisms (structures/altars/raids) that don't go through the BestSpawner, and the label protection guarantees wild legendaries are never swapped by the random spawn system. The outbreak shiny boost reads Cobblemon's shinyRate config at runtime, automatically respecting the pack's improved 1:2048 rate.

This was validated by running a full dedicated server with all 135 Cobbleverse mods plus this one — clean boot, no conflicts.

Compatibility & portability

This mod uses only Cobblemon's public API (the ENTITY_SPAWN, POKEMON_CAPTURED, POKEMON_FAINTED and BATTLE_FAINTED events plus the data-driven spawn pool format) — zero mixins into Cobblemon internals. This minimizes breakage across future updates. The declared dependency accepts >=1.7.3 <1.8.0; to update, bump the version in build.gradle.kts and fabric.mod.json.

Dependencies:

Cobblemon (required)
Fabric API (required)
Fabric Language Kotlin (required)

Known limitations (v1.1.0)

Chat messages are translated client-side (English and Brazilian Portuguese included); players joining without the mod on their client will see raw translation keys in chat
Outbreaks always pick surface positions (heightmap)

Building

./gradlew build      # jar lands in build/libs/
./gradlew runClient  # test client

License

MIT