Beat Bio-Bulkhead Fast in Borderlands 4 — Grapple, Toss Locust Capsules, and Aim for the Head
Bio-Bulkhead is one of the first major bosses in Borderlands 4, and you’ll need your grappling hook to reach and damage it properly. Although its tough exterior blocks raw firepower, a few clear mechanics make the fight predictable — and beatable — once you know what to do.
Bio-Bulkhead location in Borderlands 4
Bio-Bulkhead appears at the end of the “One Fell Swoop” quest. Specifically, you find it inside Sol’s production facility in the Synthetic Nave region of the Dissected Plateau. First, you escort Zadra into the lab area, then clear enemies and manipulate environment objects to reach the boss room.
To open the shielded door, use the air duct on the northwest side of the room to enter the lab. After that, kill the enemies, pull a lever to collect a Locust sample, and use your grappling hook to grab capsules and throw them at the gate. Repeat the capsule throw in the room where Zadra is, then move on; you’ll pass a couple of vending machines before hitting the arena.
Bio-Bulkhead’s moveset
Several androids spawn during the fight and will keep harassing you. However, try to keep at least one alive: if you go down and enter “Fight for Your Life”, a live enemy lets you get back up by downing it.
The boss uses a regenerating shield that blocks all damage. You can tell the shield is active when lines cross over the health bar. To temporarily disable it, throw Locust capsules at the shield from the capsule spawn points. You’ll find capsules in the northern part of the lower level and the southern part of the upper level of the arena.
Distance and movement are key. Bio-Bulkhead chases you and can close gaps quickly, so use stairs and pillars for cover, stay mobile, and aim for the boss’s head to deal the most damage. The shield returns multiple times during the fight; in testing it reactivated about three times.
Jump attack
Bio-Bulkhead jumps and creates a shock wave where it lands, followed by an electrified area. If you’re far enough away the jump isn’t dangerous, but after a gap-closer you may need to glide with your backpack and dash out of the landing zone.
Frontal shock wave
Slamming both hands into the ground sends a long-range shock wave forward. These travel far, so sidestep or glide to the side rather than trying to outrun them straight back.
Blue projectile
The boss generates a blue projectile (sometimes two) that flies in an S-shaped path. It’s tricky to dodge, so time a dash as it approaches to avoid damage.
Gap closer
When you stand far away, Bio-Bulkhead will leap to your position. Running away can work, but often the faster counter is to dash toward where it’s landing, which gives you room to avoid follow-up attacks.
Bio-Bulkhead rewards
Defeating Bio-Bulkhead gives experience and loot. The drops are random, but notable possible legendary items include the Sho Kunai, Waterfall grenades, and the Budget Deity pistol. After the fight there’s also a red chest in the area that can contain good gear.
For reference, early runs at level 15 rewarded about 486 XP. A later run at level 35 in Ultimate Vault Hunter mode (Rank 1) returned around 2,080 XP. You can replay the fight via Moxxi’s machine for a fee, like other boss encounters.
