Fury From Beyond

Prerequisite: Half-orc or Orc
Your Orcish heritage lets withstand death. You gain the following:

• Increase your Constitution score by 1.
• Once per long rest, when you drop to 0 hit points, you may choose to not become unconscious, and instead keep acting normally. You must make death saving throws, however, and you die if you fail three times. If you succeed three times, this effect ends and you gain 1 hit point.
• You can’t be stabilized while you continue fighting and casting spells at 0 hit points, except by healing. You may end this effect as a bonus action while you remain at 0 hit points, and all normal rules for that situation take over.

Volo's Complete Subrace Handbook by Clan Crafter Hralding. DM's Guild