Interposing Reaction (5e Feat)
From D&D Wiki
Prerequisites: Constitution 13 or higher, Dexterity 13 or higher
* You increase your constitution by 1 point, to a maximum of 20.
- When you see an ally within your range of movement being attacked, you can choose to take their place for the blow, knocking the ally prone in a square adjacent to you and free of harm. This attack hits you no matter your AC, and you take damage as if it had. This includes spell attacks, melee attacks, and ranged attacks.