Undead Fortitude. If damage reduces the bogwatcher to 0 hit points, it must make a Constitution saving throw with a DC of 5 + the damage taken, unless the damage is radiant or from a critical hit. On a success, the bogwatcher drops to 1 hit point instead. Buried. While underground, the bogwatcher is completely covered and invisible to the naked eye.
Slam. Melee Weapon Attack: +3 1d20+3 to hit, reach 5ft, one target. Hit: 4 (1d6+1) 1d6+1 bludgeoning damage. Bury. When underground, bogwatchers can attempt to grab onto any creature within a 5ft range and pull them down. The targeted creature must make a Strength saving throw; if failed, the creature is pulled down into the mud and restrained. On their turn, the creature can use an action to make a Strength saving throw; on a successful save, the creature pulls itself from the mud and is no longer restrained.