From Pathfinder Lost Omens Cheliax, Infernal Inheritance, which isn't enabled.

Shadowbound Mare

CREATURE 4

LARGE ANIMAL SHADOW

Prized by those who hunt elusive and incorporeal prey, these mares have a reputation for steadfastness.

Perception +11; darkvision

Skills Acrobatics +10, Athletics +12, Stealth +10

Str +5, Dex +3, Con +3, Int -4, Wis +2, Cha -1

AC 20; Fort +12, Ref +11, Will +8

HP 60; Immunities bleed, paralyzed; Resistances physical 5 (except ghost touch)

Buck

Reflex

Most monsters that serve as mounts can attempt to buck off unwanted or annoying riders, but most mounts will not use this reaction against a trusted creature unless the mounts are spooked or mistreated.

Trigger A creature Mounts or uses the Command an Animal action while riding the monster.

Effect The triggering creature must succeed at a Reflex saving throw against the listed DC or fall off the creature and land Prone. If the save is a critical failure, the triggering creature also takes 1d6 bludgeoning damage in addition to the normal damage for the fall.

Speed 40 feet

Melee Hoof +12, Damage 2d8+5 bludgeoning

Gallop

The shadowbound mare Strides twice. It has a +10-foot circumstance bonus to its Speed during these Strides.

Light Vulnerability

Attacks against the shadowbound creature are treated as magical if made by a creature that's in magical light or with an object that's in magical light (such as from the light spell).

Shadow Form (concentrate, polymorph, shadow)

A shadowbound creature can assume a shadowy form. In this state, the creature gains the incorporeal trait. It has resistance 10 to all damage (except force, ghost touch, spirit, or vitality; double resistance vs. non-magical), is immune to precision damage, and can't use any actions with the attack or manipulate trait. It has a fly Speed of 15 feet and can slip through tiny cracks. The shadowbound creature can Dismiss this effect to become solid again, but if it does so in an area of bright light, it's Stunned 1 for 1 round.

Shadow Touch

The creature's Strikes affect incorporeal creatures with the effects of a ghost touch property rune.

Pathfinder Lost Omens Cheliax, Infernal InheritanceORC