Pegasus

A pegasus on the party's side is a flying mount with opinions. Chaotic Good Celestial, understands Celestial, Common, Elvish, and Sylvan but does not speak any of them, which makes every interaction a dialogue of nods and refusals. Treat it as an NPC with strong moral instincts and a 90 ft. fly speed, and the scene writes itself.

The setup is consent. A pegasus chooses its rider, and the choice is rarely the highest-Charisma party member. Run the meeting as a moment of mutual recognition: maybe the paladin's oath, maybe the druid's quiet patience. Once accepted, the pegasus carries the rider at 90 ft. of fly with a Large carrying capacity, enough for light or medium armor. It will not carry chains, slaves, or anyone the rider has lied to it about. If the party tries to load contraband, the pegasus refuses to lift off and the rider has to figure out why.

In a fight, the pegasus is a hit-and-run platform. The rider takes the shot from above, the pegasus uses its 90 ft. fly to clear out, then loops back next round. If forced to engage, Hooves at +6 with 5 ft. reach land 7 bludgeoning plus 5 radiant for 12 average per hit. One attack per round, no Multiattack. This is a courier with hooves, not a damage dealer. Passive Perception 16 catches ambushes the party misses, and the pegasus will spook visibly when something invisible is nearby. Use that.

The exit comes when the pegasus's purpose is served. If a higher celestial sent it to escort the party through one journey, it leaves at the destination and does not stay for the wedding. If the rider has bonded with it across a campaign, the pegasus stays as long as the rider remains worthy. The threat of losing the pegasus is half the reason to give the party one.

Have the pegasus refuse to fly on the morning after a moral compromise. Don't explain. Let the table figure out what changed.

A pegasus as adversary is a real stretch and needs a hard setup. The plausible frames are corruption (a Sphere of Annihilation grazed it, an evil wizard's geas binds it, a fallen celestial's whisper has tipped it) or mistaken identity (the party is wearing the colors of a faction the pegasus has been told to attack). Sell the corruption or the misunderstanding for at least one full scene before the fight, because a hostile pegasus the party can't reason with is a tragedy at the table.

Mechanically the pegasus is a CR 2 skirmisher with one trick. Open from 90 ft. of altitude, dive in for a single Hooves attack at +6 (12 average, 7 bludgeoning plus 5 radiant), and use the remaining movement to climb back out of melee reach. There is no Multiattack and no breath weapon, so the damage ceiling is low, and the encounter is about denial rather than killing. Force the party to choose between chasing the pegasus with ranged attacks and dealing with whatever else is on the field. AC 12 and 59 HP make the pegasus fragile, so if the party can pin it on the ground for one round, they win.

The off-ramp matters. A corrupted pegasus that drops to 0 HP should not die. Lesser Restoration, Dispel Magic, or a paladin's Lay on Hands at the right narrative beat ends the influence and leaves the pegasus alive, exhausted, and ashamed. The party gets a friend out of an enemy, which is the only ending that does the creature justice. If they kill it without trying for that exit, mark it down. The forest remembers.

Telegraph the corruption visibly the round before initiative drops: black foam at the mouth, eyes the wrong color. The party should know there is a save here before they have to make it.