The Spiked Armor can be found in Sword Coast Adventurer’s Guide, page 121.
While wearing this armor, you can use it to cast either Speak with Dead or Animate Dead. Once the armor has cast a spell in this way, it can't cast either spell until the next dawn.
Your soul keeps this armor together. If you die while you are attuned to the armor, the armor is destroyed.
Spiked armor is a rare type of medium armor made by dwarves. It consists of a leather coat and leggings covered with spikes that are usually made of metal.
The wearer has Disadvantage on Dexterity (Stealth) checks.