Web Walker. The spiddler crab ignores movement restrictions caused by webbing.
Multiattack. The spiddler crab makes two attacks: one with its bite, and one with one of its claw. Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 10 (2d6+3) piercing damage plus 4 (1d8) poison damage. Claw. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 10 (2d6+3) bludgeoning damage. If the target is charmed by the spiddler crab, this attack is rolled with advantage, and deals an additional 16 (3d10) bludgeoning damage. Enchanting Song. The spiddler crab plays an enchanting tune. Each humanoid within 1 mile that can hear must make a DC 11 Wisdom saving throw or be charmed by the spiddler crab. A creature charmed in this way must use its movement to move towards the source of the song, until it is within 10 feet of the source. If a creature succeeds on the saving throw or the effect ends for it, that creature is immune to the spiddler crab's enchanting song for 24 hours, but cannot hear the song unless it has a passive Perception of at least 16. If the spiddler crab uses its action for anything other than its enchanting song, the effect ends for all affected creatures. Web (Recharge 5–6). Ranged Weapon Attack: +5 to hit, range 30/60 ft., one creature. Hit: The target is restrained by webbing. As an action, the restrained target can make a DC 12 Strength check, bursting the webbing on a success. The webbing can also be attacked and destroyed (AC 10; hp 5; vulnerability to fire damage; immunity to bludgeoning, poison, and psychic damage).