Patient Zero

Patient Zero

Enemy • Story

Patient Zero
Normal Index Case
Mode Appearance	Intermediate Challenges Boss Rush Events The Takeover (Pro) Originally: Casual PVP Test
Wave Debut	30 Originally: 30 (Mid Rank PVP Test) 15 (The Takeover Pro)
Statistics
Base Health	100,000 Challenges 100,000 (Boss Rush)
Defense	20%
Speed	Very Slow (1) Slow (1.6, Index Case)
Cash Given	$4,000 every 2.5% health (Intermediate) $1 every 2.5% health (Default)
Hidden?	No
Flying?	No Yes (Stomp)
Ghost?	No
Lead?	No
Attributes	Stun Immune Freeze Immune Burn Immune Boss Immunities: Freeze Immunity Stun Immunity Poison Slowdown Confusion Thorn Slowdown Nuke Fallout Damage DJ Booth Slowdown Defense Dropping Hacker Conversion Hacker Slowdown Slowed Immunity
Abilities
Ability 1Cooldown: 55	Stomp - Patient Zero jumps high and does a ground pound with its bionic fist, stunning towers for 5 seconds and dealing 400 damage to units in a wide range. Becomes a Flying enemy during this.
Ability 2Cooldown: 45	Enemy Spawn - Patient Zero summons five enemies, which can be the Living Experiment, Boomer, Ghoul or Speedy Boss.
Ability 3Cooldown: 30	Flask - Patient Zero throws blue potions onto the path, which heal enemies by 10 health every 0.1 seconds.
Ability 4Cooldown: 45	Toxic - Patient Zero lowers its goggles and fires four toxic orbs out of its right arm at towers or units multiple times, which increase the firerate of towers caught in the splash range by 150% with its 60% Firerate Debuff for 10 seconds and dealing 500 damage to units for each orb they were hit by.
Ability 5	Index Case - Upon reaching half of its default health (50,000), Patient Zero crouches down to the ground and injects both of the syringes on its back to the torso. It then gets back up, screams and raises its hands, making it temporarily regenerate 75 health every 0.1 seconds. It also gets 60% faster and makes red veins appear on its right arm, face and left leg.
Music
OfficialIn-Game (Official) Tower Defense Simulator OST - The Final Experiment (Patient Zero's Theme) Tower Defense Simulator OST - The Final Experiment (Patient Zero's Theme) In-Game

CurrentThe Takeover EventVersion 1

There's Patient Zero, give it everything we've got!

―Commander dialogue on Wave 30 (Intermediate)

Is that Patient Zero?! Can he even skate?!
Well, he's not going to skate better than me! Take him down!

―Commander dialogue on Wave 15 (The Takeover Event, Pro)

Wait a second... something seems off...
Is that... Patient Zero!?
No matter what, let's make sure this time it rests in pieces!

―Commander dialogue on Wave 30 (Casual)

Description

Patient Zero is the final boss of Intermediate mode. It also appears in The Takeover Event. It has a high amount of health but moves quite slowly. It has multiple immunities, making it immune to being frozen, stunned by stunning towers, slowed down by the Toxic Gunner, confused by the Jester, set on fire by towers like the Pyromancer, knocked back, slowed down by the DJ Booth, damaged by the Nuke's fallout damage or have its defense dropped, though some of these are only applied in Intermediate mode.

Patient Zero has multiple abilities:

1. The first ability, Stomp, makes it jump into the air, temporarily becoming a Flying enemy, and hit the ground with its fist while landing, stunning towers for 5 seconds and dealing 400 damage to units in a wide range.
2. The second ability is Enemy Spawn, where it spawns five enemies. These can be the Living Experiment, Boomer, Ghoul or Speedy Boss.
3. The third ability is Flask, where it throws multiple blue potions on the path, that heal any enemy, including itself, by 10 health every 0.1 seconds.
4. Its fourth ability, Toxic, makes it fire out multiple toxic orbs that apply a 60% Firerate Debuff (150% increase) on towers for 10-15 seconds. As units cannot have their firerate slowed down, they receive 400 damage for each orb they got hit by instead.
5. Its fifth and final ability is Index Case, which is rage mode. Upon reaching half of its default health, which is the one seen in the Index and Sandbox mode (50,000), it will crouch down to the ground and raise its arm, gaining a temporary passive 75 health regeneration every 0.1 seconds, faster speed and red veins on its right arm, face and left leg.

Appearance

Patient Zero is a large humanoid with a waist, lower arms and lower legs in its rig. It has a light purple skin color, a white lab coat with a purple hexagon pattern accent and collar and a glowing green core at the middle of its chest, torn navy blue pants and grey boots. Its right hand is bionic, with glowing green wires attached and a large sickly purple and light blue arm with three fingers and a blaster in the palm of its hand. Its legs are whitish purple.

It has glowing green eyes, a large grin, white hair and glowing green goggles on its forehead. These goggles will flip down when it performs the Toxic ability. It also has a yellow nametag, which displays its old, more human appearance. It also wears a large, high-tech metal backpack. When the Index Case ability activates, it will gain glowing red veins on its right forearm, legs and head, as well as red particles at the ends of its limbs. The ability activation also makes Patient Zero shake the screen whenever it takes a step.

Patient Zero has a death animation, where it will flex its right arm, quickly spin around and then fall forward. It also plays a growling sound with a thump when it hits the floor during the death animation.

Strategy

• Towers with decent DPS, like the Militant, Brawler, Ace Pilot or Military Base can be used to deal with it, though proper late-game towers like the Crook Boss, Hunter or Minigunner can also be used.
  • Support towers like the Commander, Medic and DJ Booth can be useful at boosting the statistics of these towers.
• The Commander can be useful at partially mitigating the Firerate Debuff applied by Patient Zero.
• The Medic can be used to shield towers from its debuffs, though it cannot protect them from the Firerate Debuff it applies.
• Due to its high number of immunities, most stalling towers are ineffective against it.
  • The only towers capable of slowing down Patient Zero are stunning towers like the Electroshocker and Trapper, though due to its Stun Immunity they will only be able to slow it down instead of stunning it.

Gallery

Corpse Variants

• 
  Second Corpse variant, current version (12 March 2025 – Present)

Previous Variants

• 
  First version (3 May 2024 - 18 May 2024).
• 
  First version, Index Case (3 May 2024 - 18 May 2024).

Icons

• 
  Patient Zero on the game icon.

Thumbnails

• 
  Patient Zero on the game thumbnail.

Promotional Images

• 
  Patient Zero on a promotional image.

Promotional Videos

• 
  Patient Zero on a promotional video.
• 
  Patient Zero on a promotional video.

Cutscenes

• 
  Patient Zero in the Outpost 16 opening cutscene.

Renders

• 
  Patient Zero on a render.
• 
  Patient Zero on a render.
• 
  Patient Zero on the Casual mode icon.
• 
  Patient Zero on the matchmaking icon.
• 
  Patient Zero on the Intermediate mode icon.
• 
  Patient Zero on the matchmaking icon.
• 
  Patient Zero on the Main Lobby Matchmaking mural.

Badges

• 
  Patient Zero on the Defeated Patient Zero! badge.
• 
  Patient Zero on the Defeated Patient Zero! badge.
• 
  Patient Zero on the Defeated Patient Zero! badge.

Miscellaneous

• 
  Patient Zero's smirk.
• 
  Silhouette Patient Zero on the update forecast.
• 
  Patient Zero featured in the v1.20.0 update log.
• 
  Patient Zero featured in the v1.20.0 update log.
• 
  Patient Zero featured in the v1.20.0 update log.
• 
  Patient Zero on its Index icon.

Trivia

• Patient Zero, and by extension, Intermediate mode, were originally teased through a silhouette in September of 2023 in an update forecast, being stated to release by early November of 2023.
• Prior to the 18th of May 2024, Patient Zero's grin was the Toon Face: Villain Smile from the Roblox catalog.
  • This made it the first enemy to use dynamic heads.
  • The current smile it uses appeared on all renders and promotional material at the time, however.
• Patient Zero is the first enemy that can target units using abilities.
• Patient Zero appears to be a German speaker (and possibly of German origin) according to the Intermediate mode trailer.
  • Patient Zero said one line in German that being "Jetzt ist es an mir, die Menschheit auszulöschen!".
    • Said line translates to "Now it's my turn to wipe out humanity!".
  • This is the first time a non-event enemy is seen speaking.
  • This is the first time someone is seen speaking a language other than English in promotional videos and trailers.
• Patient Zero's name comes from the noun "patient zero", used to identify the first known individual to carry a disease on an outbreak.
• Patient Zero is the second enemy to shake the screen without the use on ability, with the first being the Dummy Boss, which shakes the screen whenever one of its fists makes contact with the ground.

Update History

• 3 May 2024 - v1.20.0
  • Patient Zero added.
  • Bug: Patient Zero will continue to heal itself during and after its death animation.
  • Bug: Patient Zero is affected by the All Paths modifier.
  • Bug: Units will deal a lot of damage to the Patient Zero's regenerated health.
  • Bug: Patient Zero's animations break when stunned.
• 6 May 2024 - v1.20.1
  • Health increased from 80,000 to 100,000.
  • Now has 15% defense.
  • Bug: Poison and electric defense dropping does not reduce Patient Zero's defense.
  • Bugfix: Patient Zero is no longer affected by the All Paths modifier.
• 10 May 2024 - v1.21.0
  • Patient Zero is now immune to the fallout damage from the Nuke.
• 18 May 2024 - v1.22.0
  • Patient Zero is now immune to knockback.
  • Appearance changed.
• 19 July 2024 - v1.26.0
  • Bug: Damage Indicators do not appear on Patient Zero.
• 2 August 2024 - v1.27.0
  • Bugfix: No longer regenerates health after being killed.
• 28 August 2024 - v1.29.0
  • Bug: Can be slowed down by the DJ Booth.
• 31 August 2024 - v1.29.7
  • Bugfix: No longer can be slowed down by the DJ Booth.
• 11 September 2024 - v1.31.0
  • Cash given increased from $7,000 to $8,000 every 10% health.
• 6 November 2024 - v1.40.0
  • Patient Zero can no longer have its defense dropped.
  • Bugfix: Patient Zero's defense can now be dropped by poison and electric defense dropping towers, if it has no Boss attribute, though the Jester still cannot drop it.
• 20 November 2024 - v1.42.0
  • Bugfix: Units no longer deal high amounts of damage to its regenerated health.
• 11 December 2024 - v1.45.0
  • Now appears in Casual mode.
    • Has 60,000 health in Casual mode.
    • Gives $5,000 every 2.5% health in Casual mode.
    • Summons changed, summons the Normal Boss instead of the Ghoul, the Enraged instead of the Slime and the Hazmat instead of the Reaver.
      • Bug: Does not summon the Hazmat due to its name being misspelled as "Hazmats".
    • Index Case ability cannot be activated in Casual mode.
  • Now gives $2,000 every 2.5% health in Intermediate mode.
  • Increased Flask heal from 5 to 10.
• 16 December 2024 - v1.46.0
  • Bug: Patient Zero has no animations in its Index entry.
• 26 February 2025 - v1.55.0
  • No longer appears in Casual mode.
  • Bug: Now can summon the Giant Boss with a 5% chance.
  • Bug: Slime summon chance decreased from 30% to 25%.
• 9 April 2025 - v1.60.0
  • Now appears in Mid Rank PVP Test with 50,000 health.
• 23 April 2025 - v1.62.0
  • No longer appears in the PVP Test as it has been removed.
• 11 September 2025 - v1.74.3
  • Health decreased from 100,000 to 25,000 in Sandbox mode.
• 12 September 2025 - v1.74.3a
  • Now appears in Sk8 P4rk Pro difficulty as part of The Takeover Event.
    • Has 25,000 health in Sk8 P4rk.
• 22 September 2025 - v1.74.3g
  • No longer appears in Sk8 P4rk, as it has been removed.
• 28 January 2026 - v1.84.0
  • Health increased from 25,000 to 100,000 in Sandbox mode.
  • Defense increased from 15% to 20%.
  • Stomp ability changed.
    • Stun time increased from 3-5 to 5.
    • Damage increased from 250 to 400.
      • Now temporarily gains Flying.
  • Enemy Spawn ability changed.
    • Number of enemies summoned decreased from 6 to 5.
    • Now summons Living Experiment, Speedy Boss and Boomer.
    • No longer summons Reaver, Slime and Giant Boss.
    • Cooldown increased from 35 to 45.
  • Index Case ability changed.
    • Health regen increased from 50 to 75.
    • Now properly triggers at half health.

Intermediate
Previous Debut	Current Debut	Next Debut
Giant Boss Wave 28	Patient Zero Wave 30	N/A End

Pro (The Takeover)
Previous Debut	Current Debut	Next Debut
Failed Experiment Wave 13	Patient Zero Wave 15	N/A End