Bone Cage

The bones within dead creatures around you rip and tear out of their body and surround the caster protecting them for a short time. For each dead creature within 60 feet the caster gains 1 AC. Constructs are immune to this as well as any creature that simply lacks bones, but the DM has ultimate say in what this effects such as targets with massive bones such as dragons and giants. Undead targets are not effected by this as they are commanded by another master, however if the caster has undead controlled by them they may sacrifice them for this spell to take effect.