Deep Magic Volume 2 (p.154)
Concentration Smash
1-level Abjuration
Casting Time: 1 bonus action
Range/Area: Self
Components: Verbal, Somatic
Duration: 1 round
Damage/Effect: Debuff
The next attack you make before the start of your next turn has advantage if the target of the attack is concentrating on a spell. If the attack hits, the target has disadvantage on the Constitution saving throw it makes to maintain concentration after being damaged by your attack. If the attack is a critical hit, the target automatically fails the saving throw to maintain its concentration.
Available for: Paladin, Ranger