Day 92, 12:00, for 8 hours: 148 zombies at ×20 health and ×22 attack.
Part of Endless tier 19, day 2 of 5.
When it ends:
Scrap Metal
Broken Glass
All-Purpose Strengthener
Fine Sheet Metal
Instant Spicy Hotpot
Inspirational Story (Endless rewards, tiers 15-19)