Multiattack

The giant water scorpion makes two claw attacks. If it is grappling a creature, it can use its proboscis once.

Proboscis

Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 8 (1d10 + 3) piercing damage, and the target's Strength score is reduced by 1d4. The target dies if this reduces its Strength to 0. Otherwise, the reduction lasts until the target finishes a short or long rest.

Claws

Melee Weapon Attack: +5 to hit, reach 10 ft., one target. Hit: 6 (1d6 + 3) piercing damage. The target is grappled (escape DC 13) if it is a Medium or smaller creature and the scorpion doesn't have another creature grappled.