Day 25, 12:00, for 18 hours: 63 zombies at ×6 health and ×4 attack.
Part of Endless tier 5, day 5 of 5.
When it ends:
Scrap Metal×2
Broken Glass
Door Repair Kit
All-Purpose Strengthener×2
Fine Sheet Metal
Beef Noodles
Entertaining Magazine (Endless rewards, tiers 5-7)