Amorphous. The mote can move through a space as narrow as 1 inch wide without squeezing.
Blight touch. Melee weapon attack: +3 to hit, reach 5 ft., one target.
Hit: 4 (1d6 + 1) necrotic damage.
Mucous splatter. When the mote is reduced to 0 HP, it explodes into a 5 ft. square of slick slime. Any creature in that square (or entering it for the first time on a turn) must succeed on a DC 11 DEX Save or fall Prone. This slime lasts for 1 minute and is difficult terrain.
Modular vitality. Half of all damage done to blight kraken tentacles is also done to the head.
Reel. At the end of the head's turn, every tentacle currently grappling a creature moves 10 ft. toward the head.
Bite. Melee attack: +5 to hit, reach 5 ft., one target.
Hit: 8 (1d10 + 3) piercing + 2 (1d4) acid damage.
Sludge Spit (Recharge 5-6). All creatures in a 15 ft. cone must succeed a DC 12 DEX save or take 9 (2d8) acid damage and become restrained. A creature can use its action to make a DC 10 STR check to free itself or another creature from the sludge, ending the effect on success.
Sirens Call. If the head has fewer than 40 HP, as an action any un-submerged creatures within 60 ft. must succeed a DC 12 WIS save or, on their next turn, move toward the head by the shortest most direct route.
The head can take 2 legendary actions, choose from the options below. The head regains spent legendary actions at the start of its turn.
Lash (1 action). One tentacle makes a slam attack OR moves its speed.
Regrowth (1 action). If fewer than 4 tentacles are active, the head may spend 10 HP to regrow a destroyed tentacle. It appears in any unoccupied space within 30 ft. of the head.
Erupt (1 action). A new blight mote climbs out of the water or a geyser within 30 ft.
Shallow Hunter While in shallow water, the tentacle's speed is reduced to 10 ft.
Slam. Melee attack: +4 to hit, reach 10 ft., one target.
Hit: 4 (1d4 + 2) bludgeoning damage.
Constrict (Recharge 5-6). Melee attack: +4 to hit, reach 10ft., one target.
Hit: 4 (1d4 + 2) bludgeoning damage, and a large or smaller target is grappled (escape DC 12). Until the grapple ends the target is restrained, and the tentacle can't use Constrict or Slam.
Crush. a grappled creature takes 2 (1d4) bludgeoning damage.