The SerpentKing

About

The Serpent King is a standalone boss fight in its own plugin, SerpentKing. It's designed as a bigger, faster, flying cousin of the Ancient Serpent found in the Snake plugin's Deep Dark — same sculk-and-deepslate palette, same venom profile, same brutal aggression, but scaled up to a 300-block flying apex that ignores terrain entirely.

It lives in its own Java package (com.example.serpentking) and requires no dependency on the Snake plugin to compile or run. However, if the Snake plugin is installed alongside it, the Serpent King will actively hunt every snake in its 300-block radius — including the Ancient Serpent itself.

Summoning & Spawning

When /spawnboss is run by a player, the boss is spawned 20 blocks directly above them in that player's world. It begins descending toward the nearest valid target within the same tick. No inventory clearing, no gear handout, no ceremony — the boss arrives exactly like any other summoned mob.

• TriggerManual only — /spawnboss command, players with the serpentking.admin permission.
• Location20 blocks above the running player's current location, in the same world.
• One per worldThe plugin tracks bosses in a per-world map keyed by World UUID — Multiverse-friendly. Running /spawnboss while one is already active in your current world replies "already active in this world" and does nothing. You can still summon one in a different world simultaneously.
• No gear givenThe player's inventory is untouched. Bring your own equipment — the boss spawns exactly like using /summon on a vanilla mob.
• Console safetyConsole cannot summon — only players. The command requires a player location to spawn above.
• On spawnA single ENTITY_ENDER_DRAGON_GROWL sound plays at the spawn location, audible to anyone nearby. That's the only cue.

Persistence & Worlds

The Serpent King uses the same persistence model as the Snake plugin's named snakes. Once summoned, it is permanent — it survives chunk unloads, server restarts, plugin reloads, and player relogs. The only ways to remove it are to kill it or run /killboss.

• Base entitysetPersistent(true) + setRemoveWhenFarAway(false) on the invisible husk. Saved to the chunk's entity data file like any other mob.
• Scoreboard tagserpent_king on the base husk — the identifier the reconstruction scan looks for.
• Startup scanRuns 40 ticks (2 seconds) after plugin enable to let Paper finish loading spawn-chunk entities. Clears any stale display entities first, then reconstructs every boss from its persisted husk. Logs a summary to console.
• Chunk-load eventsIf a boss's chunk unloaded at restart time (e.g. outside the spawn-chunk radius), a ChunkLoadEvent handler catches it when a player walks close enough — reconstruction happens 2 ticks after the chunk loads.
• Display entitiesDisplays are marked setPersistent(false) so they don't save — they're recreated whenever the boss reconstructs. Each carries a serpent_king_display tag plus a serpent_king_owner:<uuid> tag pointing back to its husk, for clean orphan detection.
• Duplicate defenceIf somehow two husks tagged serpent_king end up in the same world (bad backup, /summon abuse, etc.), only the first is wrapped. Duplicates are removed on contact with a warning logged.
• Cross-worldIf you run Multiverse or any multi-world setup, each world is fully independent. A boss in world_nether does not know about, interfere with, or contribute to the count in world_the_end.

The Silent Hunt

What the player DOES see

What the player does NOT see

Bossbar mechanics

• RangeVisible to a player iff they're in the same world as the boss and within 300 blocks of it (matching the boss's hunt range — you only see the bar when the boss could engage you).
• Update rateRefreshed every server tick (20 Hz). Players entering range get the bar added; players leaving range get it removed. Diffed against the previous tick — no churn for players already in range.
• ColorPhase 1 — purple. Phase 2 (≤50% HP) — red. Title The Serpent King in dark red, bold.
• ProgressTracks currentHP / maxHP. Updates smoothly as the boss takes damage; the bar drains to empty on death.
• Per-world isolationEach Serpent King has its own bossbar keyed by its husk UUID. With Multiverse, two simultaneous Serpent Kings (one per world) get two independent bars. Players in world A never see world B's bar.
• Spectator exclusionPlayers in spectator mode never see the bar even if they're in range — they're observing, not engaging.
• Restart-safeBossbars are registered with namespaced keys; on plugin reload the entity reconstruction reuses the existing registration if present, so bars survive /reload cleanly.

Combat Stats

The base entity is an invisible Husk with attribute modifiers applied in the constructor. The invisible flag + scaled block displays create the 300-block visual; the attributes do the actual damage math.

Permanent potion effects

• Strength IApplied at spawn, infinite duration. Upgrades to Strength IV when phase 2 triggers.
• Fire ResistanceApplied at spawn, infinite duration. Immune to fire, lava, and flame enchantments.
• Resistance IIApplied at spawn, infinite duration. Substantial blanket damage reduction on top of the Armor attribute.

Flight & Movement

Husks do not fly natively — the Serpent King's flight is driven entirely by plugin code. At spawn, the base husk has setGravity(false) so it doesn't fall, and setAI(false) so no pathfinder goal can compete with the manual velocity. Every tick, the plugin computes a normalized direction vector from the boss's position to its target's upper torso and applies it as raw velocity. Block physics stay enabled — the boss collides with terrain, keeping fights grounded in real space.

• GravityDisabled. The husk does not fall. Y-axis movement is entirely under plugin control.
• Pathfinder AIDisabled. setAI(false) kills every pathfinder goal on the husk. Without this, the RandomStroll, MeleeAttack, and LookAt goals compete with setVelocity() every tick and produce erratic, stuttering movement. All targeting and velocity logic runs in plugin code instead.
• Block collisionEnabled. The boss collides with terrain. If a target ducks behind solid cover, the boss pushes into the surface and hovers until LOS breaks and the target is dropped.
• Movement driverManual setVelocity() every server tick toward the current target, at the speed dictated by the current phase.
• FacingThe entity's yaw and pitch are updated each tick to point at the target, so the dragon-head display doesn't drift sideways.
• Idle behaviourIf no valid target is within 300 blocks (or none with line-of-sight), velocity is zeroed — the boss hovers in place.
• Close-rangeWhen within 3.5 blocks of the target, velocity is zeroed and the boss enters melee mode (see below).

Melee attacks

Vanilla Husk melee is broken on this boss — gravity-off and manual velocity overrides both prevent the mob's MeleeAttackGoal from ever firing (the pathfinder can't "reach" the target because it can't path at all). So the plugin deals damage directly whenever the boss is within attack range, on a fixed cooldown. This is why the boss actually kills things instead of just orbiting them.

• TriggerAny tick in which the boss is within ATTACK_RANGE (3.5 blocks) of its current target, provided the 20-tick cooldown has elapsed since the last hit.
• Damage sourceLivingEntity.damage(20.0, baseHusk) — the husk is the attacker for purposes of death messages, knockback direction, and damage tracking. Respects target armour and damage reduction normally.
• First hitFires immediately on first contact — the cooldown field is initialised to -999 so there's no startup delay once the boss reaches the player.
• FeedbackSound.ENTITY_WARDEN_ATTACK_IMPACT at volume 1.5 on every landed hit. Players will hear it clearly at close range.
• Independent of venomMelee damage and the proximity venom aura are separate systems. A player in melee range gets hit by both on their own timers.

Speed comparison

Flight speed is a raw velocity magnitude (blocks per tick). For reference, a sprint-jumping player moves roughly 0.35 blocks per tick.

Phase System

The boss has two phases, triggered by HP threshold. Phase 2 is one-shot — once entered, it cannot be undone, even if the boss is somehow healed back above 50%.

Abilities & Aura

Beyond raw melee damage, the Serpent King projects a venom aura matching the Ancient Serpent's profile. Any survival-mode player within an 8×8×8 cube of the boss gets hit with a triple stack of effects every 3 seconds.

• Range8 blocks in every axis from the invisible base entity (NOT from the visible head — center of the boss).
• Tick rateApplied once every 60 ticks (3 seconds). Effects overlap — standing nearby during an application refreshes the stack.
• Gamemode filterCreative and spectator players are skipped. Adventure-mode players are also skipped for the aura (but still targetable for melee).
• Aura vs meleeThe 20-damage melee attack happens via the vanilla hit animation when the boss is within range. The aura is independent and stacks on top.

Note: unlike the regular Ancient Serpent's melee-hit venom in the Snake plugin, the Serpent King's venom is proximity-based, not contact-based. You don't have to be hit to be poisoned — you just have to be close.

Targeting

Every 10 ticks (plus on the very first tick so there's no initial hover), the boss scans a 300-block radius for the nearest living entity it has line-of-sight to. The Serpent King hunts anything that breathes — but the line-of-sight gate ensures it never locks onto someone hidden behind walls.

• Range300 blocks from the base entity, cubic volume.
• Scan frequencyEvery 10 ticks (0.5 seconds), plus tick 1 so there's no idle spin-up.
• LOS checkUses Paper's LivingEntity.hasLineOfSight(Entity), which ray-casts from the boss's eye to the candidate. Blocks like fences and glass panes follow vanilla's block-opacity rules — generally LoS-transparent, so a player crouching behind a fence is still visible. Solid blocks (stone, dirt, doors) reliably break LoS.
• TiebreakNearest LOS-visible candidate wins by squared distance.
• Target stickinessOnce acquired, target is held until death, world-leave, range-leave, or gamemode switch to creative/spectator. Brief LoS loss does not break aggro. This is the deliberate trade — sealed players never get targeted, but a real fight doesn't get cheap-cancelled by ducking behind cover.
• Re-acquireWhen the boss has no current target, the next 10-tick retarget scans for a new one with a strict LoS check. So a player who has been hiding behind cover since spawn is never acquired in the first place — the boss either picks someone visible or idles.
• Idle behaviourNo valid target → the boss enters its idle wander pattern (random scouting flights with altitude soft-cap) until something becomes visible.
• Ancient Serpent?Yes — it's a snake and a living entity. A Serpent King summoned in the Deep Dark with an active Ancient Serpent nearby will result in the two actually fighting each other, assuming they have LoS.

Gallery

Screenshots of the Serpent King in worlds it has visited — sculk-pattern body, deepslate accents, and the phase-2 corruption palette. Click any image to view full size; arrow keys navigate, Esc or click outside closes.

Appearance

Visually, the Serpent King is a supersized version of the Ancient Serpent. Same base render pipeline — invisible base entity plus block displays — but scaled up across the board.

Body palette — Ancient-Serpent family

The body rotates through six materials, identical to the Ancient Serpent's deep-dark palette, so the two read as the same species lineage.

Phase 2 palette — the Corruption

At ≤50% HP, every segment's block is swapped to the phase-2 palette. The head stays a dragon head; only the body changes. The new materials keep the dark sculk-family feel but introduce crying obsidian (violet weeping tears) and sculk shriekers (orange warning rings) to signal the boss is scarred and dangerous.

Structural details

• HeadA single BlockDisplay rendering a DRAGON_HEAD block at 5× scale, oriented south at spawn. Teleported to the base entity's position every tick.
• Body80 BlockDisplay entities, one per segment. On every tick, each segment is teleported to a position along the boss's recent movement trail, creating a snake-like following motion.
• Trail mathA location-history deque stores up to 5000 recent positions. Segments are placed by walking the trail and interpolating at fixed 3.5-block intervals — so the body flows through space even during fast turns.
• Self-healingIf the head display is removed (WorldEdit, /kill @e, etc.), the boss rebuilds all displays from scratch on the next tick.
• Orphan cleanupOn plugin enable, any entity tagged serpent_king_display from a previous run is removed — prevents ghost displays after a crash or forced shutdown.

Sounds & Particles

Because there is no bossbar, atmosphere is everything. Every audio and particle cue is intentional — it's the only way the game tells the player what's happening.

Ambient loop

• Every 40t (2s)Particle.SCULK_SOUL — 40 particles in a 3-block cube around the boss, 2 blocks above the base.
• Every 80t (4s)Sound.ENTITY_WARDEN_ROAR — volume 2.0, pitch 0.45 (deep). Audible from hundreds of blocks away.

Event cues

• SpawnSound.ENTITY_ENDER_DRAGON_GROWL at spawn location, volume 3.0, pitch 0.5.
• Phase 2 triggerParticle.SCULK_CHARGE_POP × 60 at the boss's head area, plus Sound.ENTITY_WARDEN_SONIC_BOOM at volume 2.0, pitch 0.8. This is the "oh no" moment.
• DeathNo custom effects — the vanilla Husk death animation and sound play. No toast-sound, no title, no chat.

Drops on Kill

When the boss dies, it drops exactly what a vanilla Husk drops — nothing more. There is no custom reward system: no nether stars, no dragon eggs, no inventory-push to every online player. The Serpent King lives and dies like any other mob.

• Custom dropsNone. The plugin does not touch EntityDeathEvent.getDrops() beyond the standard tracking for removing the boss from its world slot.
• XPVanilla husk XP — modest, not scaled to match the boss's 2000 HP. If you want the boss to be a worthwhile XP farm, that's a configuration change you'd layer on top.
• No broadcastNo chat message, no title, no toast — the boss simply stops existing. Its displays are cleaned up automatically on the same tick.
• World slotThe per-world boss slot is released immediately, so a fresh /spawnboss in the same world works right away.

Admin Commands

All three commands require the serpentking.admin permission (granted to operators by default). The plugin defines no other commands.

Permission node

• serpentking.adminGrants access to all three commands. Default: op (server operators have it automatically). Revoke via your permissions plugin of choice to lock the commands.