Day 45, 12:00, for 18 hours: 90 zombies at ×10 health and ×8 attack.
Part of Endless tier 9, day 5 of 5.
When it ends:
Scrap Metal×2
Broken Glass
Door Repair Kit
All-Purpose Strengthener×2
Fine Sheet Metal
Electronic Components
Beef Noodles
Entertaining Magazine (Endless rewards, tiers 8-9)