Vissiwhorl

Aggressive. As a bonus action, the vissiwhorl can move up to its speed towards a hostile creature that it can see.

Ambusher. In the first round of a combat, the vissiwhorl has advantage on attack rolls against any creature it surprised.

Amorphous. The vissiwhorl can move through a space as narrow as 1 inch wide without squeezing.

Nimble Escape. The vissiwhorl can take the Disengage or Hide action as a bonus action on each of its turns.

Spider Climb. The vissiwhorl can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.

Multiattack. The vissiwhorl can use its Frightful Presence. It then makes three pseudopod attacks and one reel attack, or two pseudopod attacks and one constrict attack.

Pseudopod. Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 11 (2d6 + 5) bludgeoning damage.

Constrict. Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 11 (2d6 + 5) bludgeoning damage, and the target is grappled (escape DC 17).

Frightful Presence. Each creature of the vissiwhorl's choice that is within 60 feet of the vissiwhorl and aware of it must succeed on a DC 14 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to the vissiwhorl's Frightful Presence for the next 24 hours.

Reel. Ranged Weapon Attack: +7 to hit, range 15/30 ft., one target. Hit: 5 (1d4 + 3) piercing damage, and the target is prone and pulled 15 feet in a straight line towards the vissiwhorl.

Split. When a vissiwhorl that is Medium or larger is subjected to slashing damage, it splits into two new vissiwhorls if it has at least 10 hit points. Each new vissiwhorl has hit points equal to half the original vissiwhorl's, rounded down. New vissiwhorls are one size smaller than the original vissiwhorl.