Absorber Immunity. The Absorber cannot be damaged twice by the same type of damage

Ex : The absorber get damaged by slashing damage, Now it is immune to that damage until he is affected by another type of damage.

Matter Absorbing. When the Absorber kills a creature, it drags the corpse with new hands and absorb it within 3 rounds. When absorbed it regains 6d12 hitpoints and only a Wish can bring the creature back to life.

Legendary Resistance (2/Day). If the Absorber fails a saving throw, he can choose to succeed instead.

Multiattack. The Absorber makes a number of attacks equal to the hands it summoned

Hands Hell. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 32 (4d12+8) The damage type is the same as the Absorber current Immunity. 

Grasping Hands. Melee Weapon Attack: +10 to hit, range 10 ft., one target. Hit: # (2d12 + 8) The damage type is the same as the Absorber current immunity. if this attack hit, the target must succeed a DC 20 Athletics or be restrained, the target can reroll the check at the end of his turn

Summoning Hands. The Absorber can summon up to 5 (Max) hands out from the ground, these hands have a AC of 10 and 20 Hitpoints

Hands Shield. A dozen of hands is summoned to block the attack, +3 to AC The hands aren't permanent

The Absorber can take 2 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. Borborygmos regains spent legendary actions at the start of his turn.

Legendary Action Name (Costs 1 Actions). The Absorber do 2 Grasping Hands attack