Day 9, 12:00, for 12 hours: 9 zombies at ×2 health and ×2 attack.
Part of Endless tier 2, day 4 of 5.
When it ends: 
Scrap Paper
Scrap Metal
Five-Spice Beef Jerky (Endless rewards, tiers 1-4)
Day 9, 12:00, for 12 hours: 9 zombies at ×2 health and ×2 attack.
Part of Endless tier 2, day 4 of 5.
When it ends: Scrap PaperScrap MetalFive-Spice Beef Jerky (Endless rewards, tiers 1-4)