Eridithias's Afterclap

You choose one creature within range and force it to make a Wisdom saving throw. If the creature passes, the spell has no effect, if the creature fails it takes all the damage it has suffered since your previous turn. This damage is psychic damage.

For example, a giant has taken 30 points of cold damage, 8 points of slashing damage, and 12 points of piercing damage since your last turn. If the giant fails its Wisdom saving throw against this spell, it would immediately take 50 points of psychic damage.