Pikmin 4 Final Boss Guide: How to Beat the Ancient Sirehound

Warning: This guide contains major spoilers for the end of the Pikmin 4 campaign, including the boss's identity and story details. Read on at your own risk.

What Is the Pikmin 4 Final Boss?

The Pikmin 4 final boss is the Ancient Sirehound, a colossal space dog that serves as the climactic encounter of the main campaign. According to Pikipedia's Ancient Sirehound entry, the creature is remarkably similar to Oatchi and Moss, and characters like Yonny and Olimar speculate that it is the ancestor of all space dogs, with its descendants evolving smaller and dispersing across the universe.

Story-wise, the beast is said to be gentle by nature, but Louie mounts it and drives it into a rampage, blocking the Rescue Corps from harvesting the cell sample needed to cure Oatchi's leafified tail. When defeated, the Sirehound drops the Gift of Friendship and Louie before fleeing — and it later reappears in the credits, calmly following Moss across the surface.

Where to Find the Final Boss

The Ancient Sirehound awaits at the very bottom of the Cavern for a King, the game's final dungeon:

• Location: Cavern for a King, sublevel 20 (the last floor)
• Arena: A large circular chamber with a small southern alcove where you land; the S.S. Beagle remains parked there
• Story items: Louie and the Gift of Friendship, typically the final collectibles of the main story

Just like other series finales, the trek down the cave and the fight itself demand mastery of multiple Pikmin types, so bring a well-rounded squad.

Ancient Sirehound Stats and Phase Overview

Unlike most bosses in the series, the Ancient Sirehound fights in five distinct phases, each with its own health bar. Per the Pikipedia wiki, it has the highest total HP of any enemy in franchise history.

Across every phase, the core loop stays the same: knock the Sirehound down by weighing its tail, then swarm its exposed belly. Once it loses a health wheel, it rises, roars, and transitions to the next element.

Phase-by-Phase Attack Breakdown

Knowing what each phase throws at you is half the battle. Here is how the fight evolves:

• Phase 1 – Physical: The only phase with no hazards. Trick its charge into a fallen stalactite to trigger a head "bonk" and a woozy stun window. Watch for the jumping slam, which crushes Pikmin and rains rocks.
• Phase 2 – Ice: It spits five (later six or seven) bouncing snowballs and a rotating ice breath similar to a Blowhog's. Frozen Pikmin get charged down and eaten. Note that the Sirehound is immune to freezing during this phase.
• Phase 3 – Electricity: Rotating furball lightning crosses can spawn up to five at low health, plus a faster electrified dash and marked floor fields. When it plants itself to cast fields, it cannot move — an ideal attack window. From here on, its tail lifts out of reach except during specific moves.
• Phase 4 – Fire: Stomp attacks send ring-shaped shockwaves along the floor with a guaranteed gap behind its tail. Fireballs can ignite the idle furballs it spits, causing chain explosions.
• Phase 5 – Gloom: The Sirehound takes flight and wields the lethal gloom hazard, which kills every Pikmin type instantly — unlike earlier hazards, there is no saving affected Pikmin. Its roar panics your squad straight into puddles, so treat it with maximum caution.

How to Beat the Pikmin 4 Final Boss: Best Strategies

The Pikipedia strategy section highlights several reliable approaches for this five-phase marathon:

• Skip the Candypop Buds. Each bud on the previous floor yields only 5 Pikmin per type, and blue/white buds correspond to hazards that never appear in this fight.
• Bring Purple Pikmin. Their superior strength trivializes tail knockdowns. With 100 Purples and ultra-spicy spray, all five phases fall in just three swarms.
• Use Glow Pikmin if available. They resist most elemental attacks, and a glowmob can stun the boss outright.
• Exploit the Lightning Shock combo. As the boss becomes vulnerable, apply ultra-spicy spray, rush it with Oatchi to latch everyone on, then immediately fire a Lightning Shock to keep it stunned. This one-cycle kill works with a large Purple squad; 60 or fewer still clears phases in two cycles instead of the usual three.
• Bait the eating charge. In phases 2 through 5, the Sirehound only charges to devour panicked, hazard-afflicted Pikmin. If it catches at least one, it pauses to eat — lowering its tail. Painful, but it skips entire attack rotations.
• Reserve Lightning Shocks for the finale. In the flying gloom phase, shocking it mid-air or landing a glowmob drops its tail instantly. With enough items, you can deny it every single attack.

Frequently Asked Questions

Who is the final boss in Pikmin 4?

The final boss is the Ancient Sirehound, a giant ancestral space dog ridden into battle by Louie on the 20th sublevel of the Cavern for a King.

How much HP does the Pikmin 4 final boss have?

Each of its five health wheels holds 9,000 HP, for a total of 45,000 — the highest of any enemy in the Pikmin series, as documented on Pikipedia.

Can you save Pikmin hit by gloom in the final phase?

No. Gloom instantly kills every Pikmin type, including types that survive other hazards, so route carefully and ride Oatchi between patches.

Does the Ancient Sirehound die when defeated?

It does not. The Sirehound is knocked unconscious, drops Louie and the Gift of Friendship, then flees — later appearing docile in the credits alongside Moss. In the Piklopedia, defeating it simply puts it to sleep.

What is the fastest way to beat the final boss?

Stack Purple Pikmin, carry Lightning Shocks and ultra-spicy spray, and chain the rush-plus-shock stun combo each knockdown to clear phases in a single damage cycle.