Bond of Life
From Guild Wars 2 Wiki
Bond of Life is available to players that have trained the Bond of Life mastery, providing them with a powerful healing skill to use while mounted. When activated, your mount's health will be saved and replaced with your current health. When the effect expires, your mount will get its health back. Losing all health under the effect of Bond of Life causes you to be downed instead of being dismounted and knocked down.“
Temporarily grant your mount the use of your own health pool at the risk of being downed in your mount's place.
- Duration: 10 seconds
— In-game description [?]