Multiattack. The Scorpigator makes 2 attacks; one with its bite and one with its stinger.
Bite. Melee Weapon Attack: +8 to hit, reach 5ft., one target. Hit: 21 (3d10+5) Piercing damage, and the target is grappled (escape DC 16). Until this grapple ends, the target is restrained, the target takes 6 (1d10) Piercing damage per turn and the Scorpigator cannot bite another target.
Stinger. Melee Weapon Attack: +4 to hit, reach 10ft., one target. Hit: 8 (1d10+2) Piercing damage, and the target must make a Constitution saving throw, taking 24 (4d10) Poison damage on a failed save, or half as much damage on a successful one.
Death Roll. Melee Weapon Attack: +8 to hit, reach 5ft., one restrained creature grappled using the Scorpigator's Bite. Hit: 35 (5d12) Bludeoning damage.