Mangrove Treant

False Appearance. While the mangrove treant remains motionless, it is indistinguishable from an ordinary mangrove tree.

Grasping Roots. The treant has advantage on Strength and Dexterity saving throws made against effects that would knock it prone.

Siege Monster. The mangrove treant deals double damage to objects and structures.

Tiny Spies. The mangrove treant can communicate with mosquitos as if they shared a language. The mosquitos alert the treant to the presence of intruders, and the treant has advantage on Wisdom (Perception) checks to notice creatures within 60 feet of it.

Multiattack. The mangrove treant makes two slam attacks.

Slam. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 18 (3d8 + 5) bludgeoning damage.

Mangrove Mosquitos. The mangrove treant calls a swarm of mosquitos from its branches. The swarm of mosquitos uses the statistics of a swarm of insects, except it has a flying speed of 30 feet. The swarm acts an ally of the treant and obeys its spoken commands. The swarm remains for 1 day, until the treant dies, or until the treant dismisses it as a bonus action. The treant can have only one swarm of mosquitos at a time. If it calls another, the previous swarm disperses.