Jackal

A jackal as a willing ally is a stretch, but the desert-scout framing carries it. A nomad ranger has hand-fed a half-tame pack and follows them across the wastes; a dawn-temple acolyte has bound a single jackal to a leash of beads as a guide spirit; a clan shaman keeps three jackals as messengers between camps. The party borrows the pack for one specific scene where 40 ft. of speed and 90 ft. of Darkvision and passive Perception 15 are more useful than any combat ability.

Use jackals as scouts, trackers, and alarms. A jackal in the dark hears a footstep at 200 ft. and reacts to it; a jackal on a leash will pull toward water, toward carrion, toward any movement upwind. Send three of them ahead of the party through a ruin and they will come back or they will not, and either result tells the party something. They do not fight. The handler should be clear about that. Send a jackal at a hostile creature and the jackal yelps, snaps, and runs in a circle, doing zero damage and dying to one solid hit.

The pack works for the handler, not for the party. Without that handler the jackals lose interest in two days, drift back to wild, and start treating the party's leftovers as their own again. Treat the relationship as borrowed and short.

Give the lead jackal a name and one habit. Players will love a beast that licks the wizard's hand once per night and is otherwise indifferent.

A jackal alone is a punctuation mark. CR 0, 3 HP, no listed attacks, walk speed 40 ft., 90 ft. Darkvision and Passive Perception 15 mean this is not an encounter, it is a sound at the edge of camp and a pair of eyes catching firelight. Any PC kills a single jackal in one swing if it lets them get close, and a jackal almost never lets them.

Run jackals in packs and run them as harassment. Six to twelve on the perimeter of a desert camp are not there to win a fight; they are there to bleed the party of sleep and arrows and nerve over a long night. Stealth +4 keeps them mostly invisible in scrub at night, and the 40 ft. speed lets a pack flicker in, snatch a loose ration sack, and be gone before the party gets a torch lit. The stat block has no codified bite, so play attacks as opportunism: a jackal within 5 ft. of an unarmored target makes a contested Strength check to drag away a pack or a pouch. If you must roll damage, a 1d4 piercing nip is honest, but the point is theft.

Target priority is whatever can be dragged. The dropped potion, the sleeping mage's spell component pouch, the kill the party was planning to butcher in the morning. Two jackals working a target together is the trick: once one PC chases the first jackal, the second is already running the other way with the prize.

Jackals scatter the moment a real weapon comes out. Drop one and the others are gone in three rounds, regrouping on the next ridge to watch. They will follow the party for days and the paranoia is the encounter.

Have the players roll one Survival check before they sleep. On a failure, they wake up missing one specific thing each.