Armor of Agathys

1st-Level Abjuration Spell (Warlock)

Casting Time: Bonus Action
Range: Self
Components: V, S, M (a shard of blue glass)
Duration: 1 hour

Protective magical frost surrounds you. You gain 5

Temporary Hit Points are granted by certain effects and act as a buffer against losing real Hit Points. See also Damage and Healing.

. If a creature hits you with a melee attack roll before the spell ends, the creature takes 5 Cold damage. The spell ends early if you have no

Temporary Hit Points are granted by certain effects and act as a buffer against losing real Hit Points. See also Damage and Healing.

.

At Higher Levels: The

Temporary Hit Points are granted by certain effects and act as a buffer against losing real Hit Points. See also Damage and Healing.

and the Cold damage both increase by 5 for each spell slot level above 1.

Source: Player's Handbook, p. 243