Day 72, 12:00, for 8 hours: 95 zombies at ×16 health and ×14 attack.
Part of Endless tier 15, 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)