Core Spawn Seer

The seer can traverse through nonmagical, unworked earth and stone. While doing so, the seer doesn't disturb the material it moves through.

The seer has advantage on saving throws against spells and other magical effects.

The seer uses Fission Staff twice, Psychedelic Orb twice, or each one once.

Melee Weapon Attack: +8 to hit, reach 5 ft., one creature. Hit: 9 (1d6 + 6) bludgeoning damage plus 18 (4d8) radiant damage, and the target is knocked prone.

The seer hurls a glimmering orb at one creature it can see within 120 of it. The target must succeed on a DC 19 Wisdom saving throw or take 27 (5d10) psychic damage and suffer a random condition until the start of the seer's next turn. Roll a d6 for the condition: (1-2) blinded, (3-4) frightened, or (5-6) stunned.

When the seer is hit by an attack, it takes only half of the triggering damage. The first time the seer hits with a melee attack on its next turn, the target takes an extra 1d6 radiant damage.