Herbert summons a glowing mace of Pelor behind Strahd to bash him.
Spoiler
Spiritual weapon, with advantage
(1d20+8)[24] or (1d20+8)[16]
Damage (1d8+4)[5] force damage
Crit bonus (1d8)[7]+4? Don't remember how we're handling crits.
If it's max + roll then 12+11=23