Iron Spikes Blood (POI)
Spike traps are your first and earliest line of defense. They slow down and damage enemies. Place them using the secondary action.
Repair with Wood or Forged Iron.
Upgrade path
Hit a placed block with a stone axe, claw hammer or nail gun while carrying the material of the next step: 4 hits per upgrade.
When its hit points run out it becomes 
Iron Spikes Trap 1.
Drops when destroyed
Iron× 10-20
Where to find (11 POIs)
Crack-a-Book HQ (tier 5), Minotaur Theater (tier 5), Navezgane Athletics Complex (tier 5), Navezgane General Hospital (tier 5), U.S. Army Post #7 (tier 5), Dumpsy Clinic (tier 4), The Zavislak Residence (tier 4), Bob's Boars & Carl's Corn (tier 3), Fort Razor (tier 3), The McLemore Residence (tier 2), The Wagner Residence (tier 2).
Points of interest built with this block (any of its variants), the highest tiers first, from the game's prefab files.