Eldritch Ulitharid

Actions

Multi-attack. The Eldritch Ulitharid can make 2 claw attacks as its action.   Claw. Melee Weapon Attack. +6 to hit, reach 5 ft., one target. Hit: 9 (2d6 + 3) slashing damage.   Mind Blast (Recharge 5-6). The Eldritch Ulitharid magically emits psychic energy in a 60-foot cone. Each creature in that area must succeed on a DC 17 Intelligence saving throw or take 45 (5d8 + 5) psychic damage and be paralysed for l minute. A target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.   Capture. As an action the eldritch ulitharid can force a creature onto the ground to restrain it. The creature must be within 5 foot. The creature must make a strength saving throw (DC 15) or be knocked prone, grappled and restrained. On a success the creature resists the push and is not prone or restrained but is still grappled but the eldritch ulitharid.   Extract Brain. Melee Weapon Attack: +9 to hit, reach 5 ft., one incapacitated humanoid grappled by the eldritch ulitharid. Hit: 55 (10d10) piercing damage. If this damage reduces the target to 0 hit points, the ulitharid kills the target by extracting and devouring its brain.

Lair Actions

Lightning Coil. At initiative 20 a large lightning coil in the centre of the chamber erupts in lightning energy. Any creature within 20 feet of the coil make make a DEX saving through or take 12 (4d6) lightning damage. On a success the creature takes half damage   Tentacle bath. If a creature end their round within 10 feet of the bath the tentacles will instinctively grab them. There are 5 tentacles total. A creature being grabbed must make a strength save (DC 13) or be grappled this save can be rolled again and the end of a creatures turn. At initiative order 20 the tentacles will force any creatures that have been grabbed under the water. While underwater then need to hold their breath unless able to breathe in water.   While underwater the lightning damage from the coil is doubled.

There must be a bath that is able to hold the elder brain form once it has been completely transitioned. To further assist there would be mechanical arm that hold and restrain the elder brain within the water during the final stages at the Eldritch Ulitharid experiences severe pain.   There is also evidence of regular feeding and consumption, as well as a form of light, the surgery and intricacy needed to safely turn requires good conditions that darkvision is not typically able to provide. Further energy is needed to generate and power the machinery so lightning coils and electrical power systems run throughout the laboratory.

When an Ulitharid approaches the end of their first life the lucky and powerful few who were able to segregates and form a a colony begin the transformation into an Elder brain. This process is long, painful and strenuous. When found in this halfway state Eldritch Ulitharid's are prone to more animalistic tendencies. Lashing out unprovoked and attacking with wild abandon. It's tentacles begin to fall away and its brain swells uncontrollably, forcing the abomination to move on all fours and drag itself around. To feed it not tackles and restrains physically since it no longer ha tentacles to hold instead. There is also the need to have a bath created for when the transformation is complete to hold the elder brain. The construction of this is also volatile and require some dangerous sciences to complete.

Underdark in a designated lair. Mobility is no longer a serious option so the eldritch ulitharid is forced to stay put