Armored Core 6: How to beat the Sea Spider boss

Arrmored Core 6
(Image credit: Bandai Namco)

Armored Core 6's second act closes with a fight against Sea Spider, a Coral-infused mechanical spider that unleashes a blitz of armor-melting laser blasts. The Sea Spider's overwhelming spread of weapons and confusing angles of attack mean that it can easily atomize even a heavyweight AC in just one or two attacks. The trick to beating this Hollywood producer's ultimate fantasy is all in the legs—both his and yours.

Here's my strategy for taking down the Sea Spider, and the AC build to make it happen.

Best AC build for the Sea Spider

(Image credit: FromSoftware)
  • Right arm weapon: Gatling gun
  • Left arm weapon: Pile bunker
  • Back weapons: Songbirds, 10-cell missile launcher
  • Head: DF-HD-08 Tian-Qiang
  • Core: CC-3000 Wrecker
  • Arms: Nachtreiher/46E
  • Legs: VP-424
  • Booster: BST-G1/P10
  • FCS: FCS-G2/P05
  • Generator: VP-20C

This build is all about using heavy weapons to keep the Sea Spider in near-perpetual stun for the first phase, and using quad legs to get the AC up above it for when it goes airborne in the second. It's possible to run two Songbirds instead of one, but I find the missile launcher makes it easier to keep the pressure on during the second phase, where opportunities for staggering are made more difficult because of it's erratic flight pattern.

How to beat the Sea Spider, the chapter 2 Ocean Crossing boss

Boss attacks to watch for

  • Two legged stomp: The Sea Spider will rear up, bare two laser daggers on two of its feet, and clamp down with explosive force. This attack can be easily dodged by quick boosting directly under the Sea Spider, and is a great opportunity to follow up with a charged pile bunker shot to the center
  • Charged laser shot: The Sea Spider will dash backwards, charging up a high-powered laser cannon. This attack can be blocked by quick boosting at an angle towards the Sea Spider, causing the laser cannon to track your AC downwards and blocking the shot with its leg
  • Laser wave: At the start of the second phase, the Sea Spider will transform into a hovering, petalled rose, charging a gigantic coral energy blast that shoots out a damaging wave. Use your quad legs to match altitude with the Sea Spider when it begins to charge the cannon and you'll avoid both the blast and the shockwave
  • Beyblade lasers: I don't even know what to call this one. The Sea Spider will start spinning around on one side, rotating lasers on its appendages. This attack is an almost instant kill if you get hit by the blades successively, so try to identify the lowest point of the craft and match pace with that. Overboosting into the corners of the arena is viable, if you can get there safely

Quick strategy tips

  • Get aggressive (in phase 1): The Sea Spider is not able to diffuse ACS build-up easily, especially during the first phase. Keep close and use charge attacks with the pile bunker to keep it in a near-constant stun lock loop
  • Get defensive (in phase 2): Once the Sea Spider lifts off in the second phase, match its altitude and keep the pressure up from a distance. Hanging out in the air will make most of it's AOE attacks redundant, and the tracking on the laser attacks is predictable enough to reliably dodge. When it becomes staggered, close in and try to get off a charged attack with the pile bunker
  • Air superiority: The Sea Spider's top cover is pretty limited, so if you find yourself right on top of it in the second phase, it's safe to dive down and get a charged melee attack off.

Pretty much all you need to know is in the first two quick tips there. The Sea Spider can seem terrifying with its intense bursts of damage, but these can be avoided outright with a good quad leg setup. once you get a feel for the rhythm of its attacks and when to keep off the ground, victory comes easy.

Nova Smith
Contributing Writer

Nova Smith is a freelance writer based out of Alberta, Canada. Nova's grab bag of non-gaming interests and passions includes Japanese mecha anime, miniature painting, as well as history, literature, and classical music. Nova also moonlights as a bureaucrat and amateur historian.