Mod of Redemption/Patient Zero

Patient Zero is a post-Moon Lord. He is the final boss of the, and will allow the player to deactivate all the laser security systems permanently.

While Patient Zero is alive, the music will play.

Spawn
Patient Zero is found dormant in the final room of the 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.

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, 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 s. 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.
 * generates in the upper layers of the Underworld.
 * s start spawning in the Space layer.
 * Chicken Invasion will be renamed to, enemies from the event will be buffed, as well as new ones start spawning during the event, including.

Tips

 * Constantly move around, the smaller s 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, or the first patient infected in an epidemic.