Hunter's Prey: Colossus Slayer is a Hunter Ranger feature gained at level 3 in D&D 5e. Your tenacity can wear down the most potent foes.
Your tenacity can wear down the most potent foes. When you hit a creature with a weapon attack, the creature takes an extra 1d8 damage if it's below its hit point maximum. You can deal this extra damage only once per turn.