Omniscience (3 charges) When an attack is made against Yog-Sothoth that requires dexterity saving throw, Yog-Sothoth has the option to change its position by 30 feet

Spell casting. Yog-Sothoth is a 3rd-level spell caster. Its spell casting ability is +5 (spell save DC 10, +4 to hit with spell attacks). Yog-Sothoth has the following warlock spells prepared:
Cantrips (at will): Poison Spray, Shocking Grasp, Ray of Frost, Vicious Mockery, chill touch, thunder clap
1st level ( 6 slots): unseen servant, illusory script                                                                              

2nd level (5 slots): Hellish Rebuke, darkness, invisibility, Ray of Enfeeblement,  suggestion, shatter                                                                                

3rd level (4 slots): counter spell, dispel magic, fear, gaseous form                                                                                                                       

Smash. Melee Weapon Attack: +6 to hit, reach 20 ft., 1 target. Hit: 2 (3d6+ 0) [bludgeoning] damage. 

Sphere Blast. RangedWeapon Attack: +2 to hit, range 20/35 ft., 1 target. Hit: 4 (2d8 + 2) [radiant] damage.

Servants of Yog-Sothoth. On its turn as a bonus action, Yog-Sothoth can summon 1D8 ghouls or 1D10 cultists.

Reality Warp. (5/Day) Yog-Sothoth can make an opponent re-roll an attack roll or saving throw.