Chaos Rune (my campaigns)

You brandish the shield used in the spell’s casting, a sigil of warding appearing on it. Until the beginning of your next turn or until the spell ends, you have a +1 bonus to AC against melee attacks. The next creature to hit you with a melee attack before then takes 1d6 damage and the spell ends, the number rolled on the d6 determines the damage type:

1 / force
2 / psychic
3 / radiant
4 / necrotic
5 / fire
6 / cold
7 / lightning
8 / thunder
9 / acid
10 / slashing
11 / bludgeoning 
12 / piercing

This spell’s damage and damage dice increase when you reach certain levels. At 5th level, the target creature takes an extra 1d4 damage and the 1d6 increases die value to 1d8. The damage rolls increase by 1d4 and one die value at 11th level (2d4 and 1d10) and again at 17th level (3d4 and 1d12).