Brain in Iron

The brain in iron can sense the presence and location of any creature within 300 feet of it that has an Intelligence of 3 or higher, regardless of interposing barriers, unless the creature is protected by a mind blank spell.

The brain in iron has advantage on saving throws against spells and other magical effects.

The brain in iron's innate spellcasting ability is Intelligence (spell save DC 15). It can innately cast the following spells, requiring no components:

At will: detect thoughts, mage hand, zone of truth

3/day each: charm person, command, hold person

1/day each: compulsion, hold monster, sleep (cast at 3rd level), Tasha's hideous laughter

The brain in iron magically emits psychic energy in a 60-foot cone. Each creature in that area must succeed on a DC 15 Intelligence saving throw or take 13 (2d8 + 4) psychic damage and be stunned for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.