Staggering Smite

Level & School
4th-level enchantment
Casting Time
Bonus action, which you take immediately after hitting a creature with a melee weapon or an unarmed strike
Range
Self
Components
V
Duration
Instantaneous
Classes
Paladin

The target takes an extra 4d6 Psychic damage from the attack, and the target must succeed on a Wisdom saving throw or have the Stunned condition until the end of your next turn.

Using a Higher-Level Spell Slot. The extra damage increases by 1d6 for each spell slot level above 4.

Level & School
4th-level evocation
Casting Time
Bonus action
Range
Self
Components
V
Duration
Concentration, up to 1 minute
Classes
Paladin

The next time you hit a creature with a melee weapon attack during this spell’s duration, your weapon pierces both body and mind, and the attack deals an extra 4d6 psychic damage to the target. The target must make a Wisdom saving throw. On a failed save, it has disadvantage on attack rolls and ability checks, and can’t take reactions, until the end of its next turn.

Staggering Smite 5.5e 2024 vs. 5e 2014 edition differences

The 2014 version deals psychic damage on hit, imposes disadvantage on attack rolls and ability checks, and prevents reactions until the end of the target's next turn. The 2024 version deals psychic damage, causes the target to be Stunned until the end of your next turn if it fails the save, and increases damage with higher spell slots.