Amalgam

Alien Mind. If a creature tries to read Amalgam's thoughts or deals psychic damage to it, that creature must succeed on a DC 17 Intelligence saving throw or be stunned for 1 minute. The stunned creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Legendary Resistance (2/Day). If Amalgam fails a saving throw, it can choose to succeed instead.

Inhuman Speed Amalgam can use a bonus action to Disengage, Dash

Multiattack. Amalgam makes two attacks with its Siegehammer. It may use its entire action to use Psychic Overload.

Siegehammer. Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit: 27 (3d10 + 11) Bludgeoning damage, plus 18 (4d8) Thunder damage if the target fails a DC 17 Constitution saving throw or half that if it succeeds. Siegehammer attacks will automatically critically hit non-magical objects or structures.

Psychic Overload (Recharge 5-6). Amalgam reaches into the mind of a creature it can see within 30 feet of it and it must make a DC 17 Intelligence saving throw. A creature takes 28 (8d6) Psychic damage on a failed save and is stunned for one minute, or half as much damage and is not stunned on a successful one. The creature may make a saving throw at the end of its turn to remove the stunned status.

Battle Senses. As a reaction, Amalgam may reduce an attack roll by (1d4) as it briefly reads the moves of the attacker.

Amalgam can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature’s turn. The skull lord regains spent legendary actions at the start of its turn.

Attack. Amalgam makes one Siegehammer attack.

Dash. Amalgam moves up to its speed without provoking opportunity attacks.

Telekinesis (2actions). Amalgam can cast Telekinesis as a legendary action.