Chair

Mundane Appearance. While Chair is motionless, it is indistinguishable from a normal wooden chair.

Constrict. When a creature starts its turn while grappled by Chair, it must make a DC 17 Strength saving throw. On a failure, it takes 3 (1d6) bludgeoning damage. 

Ambusher. On the first turn of combat, if Chair hits a creature that has not yet taken their turn in the initiative order, the hit becomes a critical hit. Chair also gets a misc. +3 bonus to Initiative rolls.

Lucky. When Chair rolls a Natural 1, they reroll. They must use the new roll.

Resistance (Frightened). Chair has advantage on saving throws to avoid being frightened.

Reductions. Chair has the following point reductions.

• Creatures attempting to track Chair roll with advantage, and Chair's Stealth checks are made with disadvantage.
• Chair cannot read or write Common or .
• Animals are naturally wary in Chair's presence.
• Chair cannot cast spells that require an S component, automatically fails Sleight of Hand checks, and cannot perform acts of fine dexterity. 

Multiattack. When Chair takes the Attack action, it can make two attacks with its Bite.

Bite. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 7 (1d10 + 2) piercing damage, and Chair attempts to grapple the target.

Mimic. Chair can mimic a sound it has heard before. A creature with reason to doubt this sound can make a DC 10 Insight check; on a success, they recognize the sound to be a mimicry.