Sand Spider

Sand Camouflage. The sand spider has advantage on Dexterity (Stealth) checks made to hide in sandy terrain.

Multiattack. The sand spider makes one Bite attack and two Impaling Leg attacks.

Bite. Melee Weapon Attack: +8 to hit, reach 5 ft., one creature. Hit: 10 (1d10 + 5) piercing damage plus 10 (3d6) poison damage.

Impaling Leg. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 12 (2d6 + 5) piercing damage. If the target is a Medium or smaller creature, it must succeed on a DC 16 Strength saving throw or be grappled (escape DC 16). Until this grapple ends, the target is restrained and takes 7 (2d6) piercing damage at the start of each of its turns, and the sand spider can't use the same Impaling Leg on another target. The sand spider has four Impaling Legs.

Trapdoor Ambush. When the sand spider is burrowed just below the surface of sand and a Medium or smaller creature enters the space on the surface just above where it is burrowed, the sand spider makes one Impaling Leg attack against the creature, bursting from the sand and revealing itself in the process. The target has disadvantage on the saving throw to avoid being grappled.