Pony

A pony is logistics with hooves. CR 1/8, AC 10, 11 HP, 40 ft. of walk, and no listed actions. The stat block does not exist to be a combat asset. It exists so a halfling, a gnome, or a child NPC can ride into the next scene without breaking your encounter math. Treat the pony as a mount-shaped vehicle with a personality the party can fuss over when they stop at an inn.

In travel, the pony's job is the carry weight. A pony hauls roughly 225 pounds at a walk and twice that for short bursts, which means a halfling barbarian's gear stops being a backpack problem. Light riders get the 40 ft. speed for tactical movement, and the pony fits through a five-foot doorway, which a riding horse cannot. For overland speed, the pony matches a normal travel pace and tires out about as fast as a person, so plan for short days if you're tracking exhaustion. If you're not, just call the day at sundown and let the pony graze.

In combat, the pony is a liability. AC 10 and 11 HP means any goblin with a shortbow drops it in a round, and the rider is now on foot in light of an enemy line. Tell the player riding it that the pony bolts the moment any creature within 30 feet attacks, with a Wisdom save for the rider to keep their seat. If the player insists the pony fights, default to a hoof attack at +2 for 1d4+1 bludgeoning, and watch it die two rounds later. The pony is not a warhorse. It knows it.

Name the pony at the table. Players who have named the pony will fight harder to keep it alive than they would for a 200 gp warhorse, and that emotional investment is the reason the SRD includes a CR 1/8 mount.

A hostile pony is a stretch, but it has a real table use: the wild herd or the haunted mount. Maybe the party has stumbled into a meadow where a stallion-led group of feral ponies sees them as predators. Maybe a necromancer has reanimated a stable and the party is pursued by a dozen small dead horses with no riders. Maybe a fey curse has pulled a child's pony into a hunting nightmare. The framing has to commit to the strangeness, because a CR 1/8 beast is not a threat by itself.

Run them in a herd of six or more. A single pony at AC 10 and 11 HP folds to one arrow. Six ponies at the same stats are a stampede, and the encounter shape is now Dex saves for prone and bludgeoning damage as the party tries not to be trampled. Default a kick to +2 for 1d4+1 bludgeoning damage, with the herd's actual threat being momentum. If a PC fails a Dex save, they're prone in the path of more hooves. The fight ends when the party kills enough of the herd to break the rest's flight pattern, or when they get behind cover and let the herd pass.

Ponies do not coordinate, and they do not surrender. Wild Int 2 and Cha 7 keep them on simple instincts: they run from fire, scatter from loud thunder, and most of all follow the lead horse until that horse drops.

If the players spare the herd, give them a chance to tame one in the next downtime. Players love a pony with a backstory.