Prismatic Shield

Armor Class: +2
This magical shield is worn as a simple clasp to
the back of the wrist and materializes when
brought up in defense. Once per rest, if an attack
against you hits with an attack roll equal to your
AC, you may use your reaction to cause the
attack to miss and diminish the creature. The
creature must roll 1d4 and substract the number
rolled from it's next attack.
Requires Attunement.