properly implement 2 mechanics

MOB_ADAPTATIONS.md

@@ -103,13 +103,13 @@ Several hostile families also have identity-specific pressure tools. These use v
 - Guardians - Focused Beam: tier 4+ guardian beam damage increases slightly when multiple guardians are already focused on the same player.
 - Elder guardians - Drowning Pressure: elder guardian beam hits add brief Slowness and a sinking pull.
 - Shulkers - Gravity Chain: tier 4+ shulker hits against an already levitating player extend Levitation and apply brief Slowness.
-- Slimes - Recombine: tier 5 small slimes gain short damage and jump pressure when they successfully hit, helping split slimes remain relevant.
+- Slimes - Recombine: tier 5 equal-size Slimes that survive for 10-15 seconds seek one another within 12 blocks. On contact, one absorbs the other and doubles in size from 1 to 2 or from 2 to 4.
-- Magma cubes - Molten Recombine: tier 5 small magma cubes use the same short damage and jump pressure as slimes, and briefly ignite the player on hit.
+- Magma cubes - Molten Recombine: tier 5 Magma Cubes use the same delayed merge behavior, but only combine with equal-size Magma Cubes and never mix with ordinary Slimes.
 - Piglins - Gold Frenzy: piglin-family Nether pressure is stronger at tier 5, while gold still remains valid counterplay rather than a hard immunity bypass.
 - Piglin brutes - Guard Break: tier 5 brute hits add a small armor-piercing damage component and briefly disable shields.
 - Hoglins - Gore Toss: tier 4+ hoglin hits can toss the player upward and backward on cooldown.
 - Zoglins - Frenzied Rampage: tier 5 low-health zoglins gain a short Speed and Resistance burst.
-- Ghasts - Splitting Fireball: treated as future work; current tier 5 ghasts already use stronger target prediction through airborne positioning and projectile aim adjustment.
+- Ghasts - Splitting Fireball: every tier 5 Ghast fireball launches two additional fireballs at shallow side angles while preserving the original center shot. Split projectiles are marked so they cannot recursively split again.
 - Blazes - Overheat Volley: tier 5 blazes that take ranged damage briefly gain Speed and Strength pressure to punish static bow farming.
 - Phantoms - Bleeding Dive: tier 5 phantom hits apply brief Hunger as a vanilla bleeding-style damage-over-time pressure.
 - Vexes - Phase Cut: tier 5 vexes that hit while phasing gain bonus hit pressure and apply brief Weakness.
@@ -363,6 +363,7 @@ AI changes:
 - Tier 2+ angled jump pressure instead of only direct movement.
 - Side positioning based on entity id so repeated slimes naturally spread.
 - Larger tier 5 slimes move and leap more aggressively.
+- Tier 5 equal-size Slimes become eligible to recombine after surviving for 10-15 seconds, seek a compatible partner within 12 blocks, and merge on contact. Two size-1 Slimes become size 2; two size-2 Slimes become size 4. Size-4 Slimes do not grow further.
 - Adaptive melee positioning.
 - Tier 4+ shared targeting.
 
@@ -376,6 +377,7 @@ Magma cubes receive shared scaling and spawn pressure through the generic hostil
 AI changes:
 
 - The same angled jump pressure as slimes, controlled by magma-cube advanced AI.
+- Tier 5 Magma Cubes use the same 10-15 second recombination cycle and 1→2→4 size progression, but only with other Magma Cubes of exactly the same size.
 - Adaptive melee positioning.
 - Nether biome tactics make them bolder in the Nether.
 - Tier 4+ shared targeting.
@@ -407,6 +409,7 @@ AI changes:
 - Airborne repositioning around targets.
 - Larger vertical offset than other airborne mobs.
 - Tier 5 target prediction for airborne positioning.
+- Tier 5 Splitting Fireball adds two shallow-angle side projectiles to each normal center fireball. The side shots retain the Ghast as owner and use its normal explosion power.
 - Nether biome tactics identify them as Nether mobs where applicable.
 - Tier 4+ shared targeting.
 

src/main/java/net/fretux/adaptivemobs/ai/AdaptiveSpecialAbilities.java

@@ -25,13 +25,12 @@ import net.minecraft.world.entity.monster.EnderMan;
 import net.minecraft.world.entity.monster.Endermite;
 import net.minecraft.world.entity.monster.Evoker;
 import net.minecraft.world.entity.monster.Guardian;
-import net.minecraft.world.entity.monster.MagmaCube;
+import net.minecraft.world.entity.monster.Ghast;
 import net.minecraft.world.entity.monster.Phantom;
 import net.minecraft.world.entity.monster.Pillager;
 import net.minecraft.world.entity.monster.Ravager;
 import net.minecraft.world.entity.monster.Shulker;
 import net.minecraft.world.entity.monster.Silverfish;
-import net.minecraft.world.entity.monster.Slime;
 import net.minecraft.world.entity.monster.Spider;
 import net.minecraft.world.entity.monster.Stray;
 import net.minecraft.world.entity.monster.Vex;
@@ -44,6 +43,7 @@ import net.minecraft.world.entity.monster.piglin.PiglinBrute;
 import net.minecraft.world.entity.monster.warden.Warden;
 import net.minecraft.world.entity.projectile.AbstractArrow;
 import net.minecraft.world.entity.projectile.Arrow;
+import net.minecraft.world.entity.projectile.LargeFireball;
 import net.minecraft.world.entity.projectile.Projectile;
 import net.minecraft.world.entity.projectile.ShulkerBullet;
 import net.minecraft.world.entity.player.Player;
@@ -60,6 +60,7 @@ import java.util.List;
 public final class AdaptiveSpecialAbilities {
 
     private static final String COOLDOWN_PREFIX = "am_special_cd_";
+    private static final String SPLIT_FIREBALL_KEY = "am_split_fireball";
     private static final List<TemporaryBlock> TEMPORARY_BLOCKS = new ArrayList<>();
     private static final List<DelayedReappear> DELAYED_REAPPEARS = new ArrayList<>();
 
@@ -75,6 +76,10 @@ public final class AdaptiveSpecialAbilities {
             return;
         }
         int tier = tier(level, mob);
+        if (tier >= 5 && mob instanceof Ghast ghast && projectile instanceof LargeFireball fireball) {
+            splitGhastFireball(level, ghast, fireball);
+            return;
+        }
         if (tier < 4 || !(projectile instanceof Arrow arrow)) {
             return;
         }
@@ -267,13 +272,6 @@ public final class AdaptiveSpecialAbilities {
             player.addEffect(new MobEffectInstance(MobEffects.LEVITATION, 80, 0));
             player.addEffect(new MobEffectInstance(MobEffects.MOVEMENT_SLOWDOWN, 50, 0));
         }
-        if ((mob instanceof Slime || mob instanceof MagmaCube) && tier >= 5 && mob.getBbWidth() <= 1.5F) {
-            mob.addEffect(new MobEffectInstance(MobEffects.DAMAGE_BOOST, 80, 0));
-            mob.addEffect(new MobEffectInstance(MobEffects.JUMP, 80, 1));
-            if (mob instanceof MagmaCube) {
-                player.setSecondsOnFire(2);
-            }
-        }
         if (mob instanceof Phantom && tier >= 5) {
             player.addEffect(new MobEffectInstance(MobEffects.HUNGER, 100, 0));
         }
@@ -338,6 +336,37 @@ public final class AdaptiveSpecialAbilities {
         return directEntity instanceof Projectile;
     }
 
+    private static void splitGhastFireball(ServerLevel level, Ghast ghast, LargeFireball original) {
+        if (original.getPersistentData().getBoolean(SPLIT_FIREBALL_KEY)) {
+            return;
+        }
+        Vec3 direction = original.getDeltaMovement();
+        if (direction.lengthSqr() < 1.0E-4D && AdaptiveAIGoalUtils.isValidAdaptiveTarget(ghast.getTarget())) {
+            direction = ghast.getTarget().getEyePosition().subtract(original.position());
+        }
+        if (direction.lengthSqr() < 1.0E-4D) {
+            return;
+        }
+        direction = direction.normalize();
+        Vec3 side = new Vec3(-direction.z, 0.0D, direction.x);
+        if (side.lengthSqr() < 1.0E-4D) {
+            side = new Vec3(1.0D, 0.0D, 0.0D);
+        } else {
+            side = side.normalize();
+        }
+        spawnSplitFireball(level, ghast, original, direction.add(side.scale(0.18D)).normalize());
+        spawnSplitFireball(level, ghast, original, direction.subtract(side.scale(0.18D)).normalize());
+        AdaptiveAIGoalUtils.debug(ghast, () -> 5, "ghast splitting fireball");
+    }
+
+    private static void spawnSplitFireball(ServerLevel level, Ghast ghast, LargeFireball original, Vec3 direction) {
+        LargeFireball split = new LargeFireball(level, ghast, direction.x, direction.y, direction.z,
+                ghast.getExplosionPower());
+        split.getPersistentData().putBoolean(SPLIT_FIREBALL_KEY, true);
+        split.setPos(original.getX(), original.getY(), original.getZ());
+        level.addFreshEntity(split);
+    }
+
     private record TemporaryBlock(net.minecraft.resources.ResourceKey<net.minecraft.world.level.Level> dimension,
                                   BlockPos pos, long expireTick) {
     }

src/main/java/net/fretux/adaptivemobs/ai/goals/AdaptiveSlimeTacticsGoal.java

@@ -9,39 +9,63 @@ import net.minecraft.world.entity.monster.MagmaCube;
 import net.minecraft.world.entity.monster.Slime;
 import net.minecraft.world.phys.Vec3;
 
+import java.util.Comparator;
 import java.util.EnumSet;
+import java.util.List;
 import java.util.function.IntSupplier;
 
 public class AdaptiveSlimeTacticsGoal extends Goal {
 
+    private static final String RECOMBINE_READY_AT_KEY = "am_recombine_ready_at";
+    private static final int MAX_RECOMBINE_SIZE = 4;
+    private static final double RECOMBINE_SEARCH_RADIUS = 12.0D;
+    private static final double RECOMBINE_DISTANCE_SQR = 3.24D;
+
     private final Slime slime;
     private final IntSupplier tierSupplier;
     private int cooldown;
+    private int recombineCheckCooldown;
+    private Slime recombinePartner;
 
     public AdaptiveSlimeTacticsGoal(Slime slime, IntSupplier tierSupplier) {
         this.slime = slime;
         this.tierSupplier = tierSupplier;
         setFlags(EnumSet.of(Flag.MOVE, Flag.JUMP, Flag.LOOK));
+        scheduleRecombine(200 + slime.getRandom().nextInt(101));
     }
 
     @Override
     public boolean canUse() {
         boolean magma = slime instanceof MagmaCube;
-        return AMConfig.ENABLE_MELEE_AI.get()
+        if (!AMConfig.ENABLE_MELEE_AI.get()
-                && (magma ? AMConfig.ENABLE_MAGMA_CUBE_ADVANCED_AI.get() : AMConfig.ENABLE_SLIME_ADVANCED_AI.get())
+                || !(magma ? AMConfig.ENABLE_MAGMA_CUBE_ADVANCED_AI.get() : AMConfig.ENABLE_SLIME_ADVANCED_AI.get())
-                && AMConfig.AI_SLIME.get()
+                || !AMConfig.AI_SLIME.get() || tierSupplier.getAsInt() < 2) {
-                && tierSupplier.getAsInt() >= 2
+            return false;
-                && slime.getTarget() != null
+        }
-                && slime.getTarget().isAlive()
+        recombinePartner = null;
-                && --cooldown <= 0;
+        if (tierSupplier.getAsInt() >= 5 && slime.getSize() < MAX_RECOMBINE_SIZE
+                && slime.level().getGameTime() >= slime.getPersistentData().getLong(RECOMBINE_READY_AT_KEY)
+                && --recombineCheckCooldown <= 0) {
+            recombineCheckCooldown = 10;
+            recombinePartner = findRecombinePartner();
+            if (recombinePartner != null) {
+                return true;
+            }
+        }
+        return AdaptiveAIGoalUtils.isValidAdaptiveTarget(slime.getTarget()) && --cooldown <= 0;
     }
 
     @Override
     public void start() {
         int tier = tierSupplier.getAsInt();
+        if (recombinePartner != null && recombinePartner.isAlive()) {
+            tryRecombine(recombinePartner);
+            recombinePartner = null;
+            return;
+        }
         cooldown = Math.max(16, 52 - tier * 5) + slime.getRandom().nextInt(25);
         LivingEntity target = slime.getTarget();
-        if (target == null) {
+        if (!AdaptiveAIGoalUtils.isValidAdaptiveTarget(target)) {
             return;
         }
         double distance = Math.sqrt(slime.distanceToSqr(target));
@@ -59,4 +83,40 @@ public class AdaptiveSlimeTacticsGoal extends Goal {
         }
         AdaptiveAIGoalUtils.debug(slime, tierSupplier, "slime angled jump pressure");
     }
+
+    private Slime findRecombinePartner() {
+        boolean magma = slime instanceof MagmaCube;
+        List<Slime> candidates = slime.level().getEntitiesOfClass(Slime.class,
+                slime.getBoundingBox().inflate(RECOMBINE_SEARCH_RADIUS),
+                other -> other != slime && other.isAlive() && other.getSize() == slime.getSize()
+                        && (other instanceof MagmaCube) == magma
+                        && other.level().getGameTime() >= other.getPersistentData().getLong(RECOMBINE_READY_AT_KEY));
+        return candidates.stream().min(Comparator.comparingDouble(slime::distanceToSqr)).orElse(null);
+    }
+
+    private void tryRecombine(Slime partner) {
+        if (slime.distanceToSqr(partner) > RECOMBINE_DISTANCE_SQR) {
+            slime.getLookControl().setLookAt(partner, 30.0F, 30.0F);
+            slime.getMoveControl().setWantedPosition(partner.getX(), partner.getY(), partner.getZ(), 1.2D);
+            return;
+        }
+        LivingEntity inheritedTarget = AdaptiveAIGoalUtils.isValidAdaptiveTarget(slime.getTarget())
+                ? slime.getTarget() : partner.getTarget();
+        partner.discard();
+        slime.setSize(Math.min(MAX_RECOMBINE_SIZE, slime.getSize() * 2), true);
+        if (AdaptiveAIGoalUtils.isValidAdaptiveTarget(inheritedTarget)) {
+            slime.setTarget(inheritedTarget);
+        }
+        scheduleRecombine(200 + slime.getRandom().nextInt(101));
+        AdaptiveAIGoalUtils.debug(slime, tierSupplier,
+                slime instanceof MagmaCube ? "magma cube recombined" : "slime recombined");
+    }
+
+    private void scheduleRecombine(int delayTicks) {
+        if (slime.getPersistentData().getLong(RECOMBINE_READY_AT_KEY) == 0L) {
+            slime.getPersistentData().putLong(RECOMBINE_READY_AT_KEY, slime.level().getGameTime() + delayTicks);
+        } else if (slime.getSize() > 1) {
+            slime.getPersistentData().putLong(RECOMBINE_READY_AT_KEY, slime.level().getGameTime() + delayTicks);
+        }
+    }
 }