When it hits
When the story calls it on the Student's run
Part of 
Aid Response Horde, starts with 
Wave 3 - Day 2.
The same wave on the other runs: Wage Slave, Warehouse Manager
Who comes, and where
50 zombies: 25 door · 25 window.
Every zombie in it has ×2.21 HP, bites ×8 as hard, bites ×1.2 as often, on top of the horde setting.
At the door 25
| Zombie | How many | At once | HP each | Bite |
|---|---|---|---|---|
| Barefoot Zombie | 5 | 2 | 177 | 8 |
| Office Worker Zombie | 4 | 1 | 287 | 8 |
| Nurse Zombie | 4 | 1 | 243 | 8 |
| Soldier Zombie | 3 | 3 | 486 | 32 |
| Hulk Zombie | 2 | 1 | 1,105 | 64 |
| Armored Crawler Zombie | 2 | 1 | 420 | 16 |
| Worker Zombie | 2 | 1 | 442 | 16 |
| Crawler Zombie | 2 | 1 | 221 | 8 |
| Brute Zombie | 1 | 1 | 575 | 24 |
At the window 25
| Zombie | How many | At once | HP each | Bite |
|---|---|---|---|---|
| Barefoot Zombie | 5 | 2 | 177 | 8 |
| Office Worker Zombie | 4 | 1 | 287 | 8 |
| Nurse Zombie | 4 | 1 | 243 | 8 |
| Soldier Zombie | 3 | 3 | 486 | 32 |
| Charger Zombie | 2 | 1 | 884 | 48 |
| Armored Crawler Zombie | 2 | 1 | 420 | 16 |
| Crawler Zombie | 2 | 1 | 221 | 8 |
| Hulk Zombie | 1 | 1 | 1,105 | 64 |
| Brute Zombie | 1 | 1 | 575 | 24 |
| Worker Zombie | 1 | 1 | 442 | 16 |
What beating it pays
A wave's total HP sets its reward tier. Each tier pays its reward, and the zombies you kill leave loot on the ground.
| Zombie Horde Intensity | Total HP | Reward |
|---|---|---|
| Weak | 14,309 | Tier 4 |
| Standarddefault | 19,078 | Tier 4 |
| Strong | 23,843 | Tier 4 |
| Very Strong | 28,598 | Tier 4 |
The game also adjusts each wave to how ready your home is (doors, defenses, supplies and how the last wave went), so the HP here is the starting point.
From the game files2
TowerWave 4125
| ID | 4125 |
|---|---|
| EventID | 52487 |
| OwnerCrisisID | 218 |
| ZombieTypeList | [9108,9110,9105,9104,9102,9109,9103,9106,9107] |
| ZombieCountList | [2,2,1,3,2,2,4,4,5] |
| MaxAliveCount | [1,1,1,3,1,1,1,1,2] |
| ChargeThreshold | 0.2 |
| TargetSlotTypes | [8] |
| AttackMultiplier | 8 |
| HpMultiplier | 2.21 |
| AttackSpeedMultiplier | 1.2 |
| SpawnAnchor | ZombieSpawn_01 |
| SpawnInterval | 2 |
TowerWave 4126
| ID | 4126 |
|---|---|
| EventID | 52487 |
| OwnerCrisisID | 218 |
| ZombieTypeList | [9108,9111,9110,9105,9104,9102,9109,9103,9106,9107] |
| ZombieCountList | [1,2,2,1,3,1,2,4,4,5] |
| MaxAliveCount | [1,1,1,1,3,1,1,1,1,2] |
| ChargeThreshold | 0.2 |
| TargetSlotTypes | [9] |
| AttackMultiplier | 8 |
| HpMultiplier | 2.21 |
| AttackSpeedMultiplier | 1.2 |
| SpawnAnchor | ZombieSpawn_02 |
| SpawnInterval | 2 |