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From Pathfinder #152: Legacy of the Lost God, which isn't enabled.

Spangled Rider's Suit

ITEM 9
UNCOMMONINVESTEDMAGICAL
Price 700 gp
Bulk 1
Category light
Group leather
AC Bonus +2
Dex Cap +3
Strength +1
Check Penalty −1

This +1 resilient studded leather is adorned with colorful sequins that sparkle in even the faintest light.

While wearing the spangled rider's suit, you gain a +2 item bonus to Command an Animal you are riding.

Any animal you ride automatically knows the Drop Prone and Step basic actions, in addition to any other basic actions it knows (normally only Leap, Seek, Stand, Stride, and Strike).

Activate (move)
Trigger You take damage while mounted or your mount Drops Prone
Effect You dismount, moving off your mount into a space adjacent to it.
Pathfinder #152: Legacy of the Lost GodOGL