Giant Scorpion

A giant scorpion on the party's side is an unusual arrangement and best played straight. A druid bonded to it, a desert ranger's trained guardian, a creature the party freed from a cult altar that has decided they're pack. Commit to the choice.

The scorpion is a 52 HP, AC 15 blocker. Use it to hold a position while the party attacks from range or maneuvers. It makes two Claw attacks and one Sting each turn, dealing solid bludgeoning and piercing plus poison damage. It won't flank, won't assist, and won't hold back to protect squishies. It hits what's in front of it.

Outside combat the Blindsight makes the scorpion a tripwire. It notices anything moving within 60 feet in complete darkness. On a night watch in the desert, have the scorpion shift and hiss. A player watching camp who notices gets to roll Perception with advantage. The scorpion can't signal eloquently, but movement is language enough.

Give the scorpion a permanent place in the party's story. A beast companion that outweighs the campaign that found it becomes part of the household.

A giant scorpion is a CR 3 predator with 52 HP, AC 15, Blindsight 60 feet, and Multiattack. It makes two Claw attacks at +5 for 1d6+3 bludgeoning each. Claws can Grapple on hit (escape DC 13). The Sting attack at +5 deals 1d8+3 piercing plus 2d10 poison. The Blindsight is the real threat. Darkness, mist, invisibility, all fail. The scorpion always knows where the party is.

Bury the scorpion in the sand. Have the party trigger it by walking across broken ground or digging. A scorpion bursting from the earth on initiative count 11 is a surprise round that hits harder than the party expects. Use the terrain to make it climb, charge through ruins, or defend a corpse or hoard.

The scorpion closes in two turns of 40-foot movement. Once it reaches a target, Multiattack into a grapple via Claw pins the target while the Sting comes next turn for 1d8+3 plus 2d10 poison. That's the kill pattern. The party must either kill the scorpion fast or break the grapple and kite. With Blindsight, kiting is harder than usual.

The scorpion has Intelligence 1 and Wisdom 9. It doesn't retreat. It fights until dead. Two scorpions on a level-3 party is a real fight. One is a speed bump with teeth. Decide before the encounter whether you want danger or a complication.

Telegraph the Blindsight the moment the party realizes Stealth didn't work. "It does not look, but it always knows exactly where you are."