Day 19, 12:00, for 12 hours: 18 zombies at ×4 health and ×3 attack.
Part of Endless tier 4, day 4 of 5.
When it ends: 
Scrap Paper
Scrap Metal
Five-Spice Beef Jerky (Endless rewards, tiers 1-4)
Day 19, 12:00, for 12 hours: 18 zombies at ×4 health and ×3 attack.
Part of Endless tier 4, day 4 of 5.
When it ends: Scrap PaperScrap MetalFive-Spice Beef Jerky (Endless rewards, tiers 1-4)