Etheric Tether

Feats

At 1st level, as a free action, a ghost rider can form an ethereal leash by connecting her soul with her ghost mount. While this leash exists, if the ghost mount's hit points would be reduced to 0 or less, the ghost rider instead transfers some of her life force to the ghost mount, healing it back to 1 hit point but taking as much damage as she heals.

Etheric Tether — Feats | Pathfinder: WotR Database