Patient Zero

Patient Zero

Statistics

Type	Boss
Environment	Abandoned Lab
AI Type	Patient Zero AI
Damage	110 / 220 (Contact) 80 / 160 (Xenium Blast) 80 / 160 (Xenium Laser)
Max Life	340,000 / 408,000
KB Resist	100%

Map Icon

Kari

Statistics

Type	Boss
Environment	Abandoned Lab
AI Type	Kari AI
Damage	110 (Contact)
Max Life	200,000 / 240,000
Defense	0
KB Resist	100%

Drops

• Item (Quantity)Rate
• Patient Zero Mask(Mod of Redemption)
  14%
• Blighted Gauntlet(Mod of Redemption)
  33.3%
• Swarmer Cannon(Mod of Redemption)
  33.3%
• Xenium Saber(Mod of Redemption)
  33.3%
• Medic Kit(Mod of Redemption)
  100%
• Mod of Redemption/Floppy Disk 6Floppy Disk 6(Mod of Redemption)
  100%
• Unidentified Blueprints(Mod of Redemption)
  100%
• Patient Zero Trophy(Mod of Redemption)
  10%
• Lab Access Panel - Master(Mod of Redemption)
  100%
• Treasure Bag(Patient Zero)

  • Heart of Infection

  100%

“

That was Kari Johansson, the father to all T-Bots and patient zero of the xenomite infection. He's been like that for 200 years, still conscious and alive in that grotesque husk.

— Loreholder, Cursed Blade

Patient Zero is a post-Moon Lord boss. He is the final boss of the Abandoned Lab and can be summoned by right-clicking on the bed in the middle of the room in the Sector Zero, the final room of the lab. He shoots lasers in patterns from his eye and sends hive growths after the player. When losing health, he also exchanges attacking with the body of the scientist Kari, the one who first hosted the infection.

Patient Zero drops some infection themed weapons, including Medic Kit, a consumable that permanently increases your health. He also drop Lab Access Panel - Master, allow the player to deactivate all the laser security systems permanently.

While Patient Zero is alive, the music Hard Technology Rock (Remix) will play.

Spawn

Patient Zero is found dormant in the final room of the Abandoned Lab named "Sector Zero". He is activated by right-clicking an object that looks like a hospital bed, found at the very bottom of the room. After his defeat, he will no longer be dormant in the room, but can still be spawned for rematches by right-clicking the bed again. He can only be summoned after all Abandoned Lab mini-bosses have been defeated.

Behavior

Attacks

When the fight starts, Patient Zero will remain dormant for a bit. Then, his eye will open and he will start pulsating to signify his awakening.

Patient Zero goes through several phases based on remaining health. Every other phase, it will hand the fight off to Kari, a smaller NPC attached to Patient Zero that serves as a secondary boss of sorts. When Kari is vulnerable, Patient Zero is invulnerable, and vice versa.

During all of Patient Zero's active phases, he will summon Hive Growths, which chase players and occasionally fire plus-shaped energy bursts.

All of Patient Zero's attacks take on the form of Xenium Blasts or Xenium Lasers. Xenium Blasts are aimed green blasts that explode on impact with a wall, splitting into six smaller blasts. Xenium Lasers are large, solid laser beams that fire in preset patterns and are given away by red warning beams.

Phase 1

Patient Zero will begin by summoning 3 Hive Growths. He is invulnerable until at least three have been killed.

During this phase, Patient Zero will attack using the following attack cycle:

• Xenium Lasers fired in a plus shape.
• Four Xenium Blasts.
• Xenium Lasers fired in an X shape.
• Three Xenium Blasts.

Phase 2 (Patient Zero at 75% HP)

Patient Zero spawns several more Hive Growths and becomes invulnerable, as Kari becomes vulnerable. Kari also attacks with a fixed attack cycle:

• Fires a barrage of green blobs at the player. These explode into gravity-affected green droplets on tile impact.

• Fires four spreads of arcing green droplets upwards.

Phase 3 (Kari at 75% HP)

Kari becomes invincible and passes the fight back to Patient Zero. Patient Zero will attack with a new attack pattern:

• Sequentially firing eight Xenium Lasers in a clockwise order.
• Firing three, 3-shot spreads of Xenium Blasts.
• Firing Xenium Lasers in a plus shape, and firing more in an X shape right afterwards. The resulting beams form an eight-pointed star shape.
• Firing three more 3-shot spreads of Xenium Blasts.

Phase 4 (Patient Zero at 50% HP)

Kari becomes the target again. He uses the same attack cycle as before, but his arcing shots fire in a wider spread and he will now fire four aimed green laser beams after his arcing attack.

Phase 5 (Kari at 50% HP)

Patient Zero becomes the target, and changes his attack cycle again.

• Fires three, 3-shot spreads of Xenium Blasts.
• Fires Xenium Lasers in an eight-way pattern.
• Fires three more spreads of Xenium Blasts.
• Fires eight Xenium Lasers in a clockwise, sequential order.

Phase 6 (Patient Zero at 35% HP)

Patient Zero spawns in a few more Hive Growths as he becomes dormant, and Kari becomes the target and switches his attack cycle.

• Fires five even wider spreads of arcing green droplets upwards.
• Fires four aimed green lasers
• Fires an aimed burst of larger green blobs. These bounce off walls once before bursting into gravity-affected green droplets.

Phase 7 (Kari at 25% HP)

Patient Zero becomes the target and switches his attack cycle one more time.:

• Fires Xenium Lasers in a plus shape and a narrow X shape, in quick succession. Once the lasers have subsided, immediately fires another burst in an eight-way pattern.
• Rapidly fires five Xenium Blasts.
• Fires Xenium Lasers in an eight-way pattern
• Fires three Xenium Blasts.

Phase 8 (Patient Zero at 10% HP)

Kari becomes the final target and attacks with all attacks in his arsenal (?)

Upon Kari's defeat, Patient Zero will die as well.

Aftermath

• Stronger enemies start spawning in the Cavern and Surface layers, which drop the materials used to fight the Ancient Deity Duo.
• Unrefined Shinkite generates in the upper layers of the Underworld.
• Star Serpents start spawning in the Space layer.
• Chicken Invasion will be renamed to King Chicken's Royal Army, enemies from the event will be buffed, as well as new ones start spawning during the event, including Rooster King miniboss.

Tips

• Constantly move around, the smaller Hive Growths take time turning so you could circle around them in a small radius quite easily.
• Despite Patient Zero's giant body, the eye is the only part you can get damaged by.
• Killing the Hive growths should be prioritized when the spawn, as they make dodging much more difficult.

Trivia

• The term "patient zero" refers to the index case, or the first patient infected in an epidemic.

Infected Scientist Mutation Stages

Infected Scientist Growth Evolution Chart

Rashes, small pustules, no crystals, skin and flesh cells die and turned into a purpleish-black color.	Stage 1
Larger pustules, disfigurement, crystals, rashes are worse.	Stage 2
3A: Uncontrollable growth of one's own bodily tissues 3B: Complete crystallization, only the bones are left inside the crystal	Stage 3A (Irradiated Behemoth)	Stage 3A (Patient Zero)	Stage 3B

History

• 0.8: New attack.​

• 0.7.8: Revamped.

• 0.7.0: Introduced.