Defense Lattice (5e Spell)
From D&D Wiki
|Casting time:||1 action|
|Components:||S, M (a stone carving of various intertwining polygons worth at least 100 gp)|
|Duration:||Concentration, up to 1 hour|
You surround yourself with a network of magic energy that solidifies into discrete barriers in response to incoming attacks.
The network starts with a pool of 20 points. Whenever a creature makes an attack roll against you that is greater than or equal to your AC, the network expends points to increase your AC by 1 per point until the end of the current turn. The network expends points until your AC is 1 point greater than the triggering attack roll, or until the amount of points spent equals 2 + this spell's spell level (whichever happens first). If you are targeted by the magic missile spell, the network expends a number of points equal to the number of missiles targeting you (up 2 + this spell's spell level) to block 1 missile per point.
In addition, when you are targeted by a spell that deals damage, you can use your reaction to expend points up to this spell's spell level and reduce the damage by 1d6 per point. If the spell forces you to make Strength, Dexterity, Constitution, or Charisma saving throws, add the number of points spent to those saving throws.
When you cast Defensive Lattice, you may choose to increase the casting time to 1 minute. The additional time is spent building and integrating an autonomous framework into the lattice, changing the spell's duration to 1 hour (no concentration required).
At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, add 5 points to the network's pool for each spell level above the 4th.