Critical Damage Effects

Credit to 5E Foundry on Tumblr.
Whenever a creature suffers a critical hit or rolls a natural 1 on a saving throw against an effect, the creature suffers an additional effect based on the damage dealt. If the creature is immune to the damage type, the effect does not occur. If there is more than one damage type present, use the one that dealt the most damage. If the damage rolled for each is a tie, the DM chooses the effect.
Acid. Any nonmagical or natural armor the creature has is removed. Their AC becomes 10+ their Dexterity modifier+ any other bonuses to AC the creature has. If the creature has magical armor, this reduction lasts for 3 rounds. If the creature has natural armor, their full AC is restored once they complete a long rest.
Bludgeoning. The creature is knocked prone.
Cold. The creature’s movement speed is reduced by 10 feet for 3 rounds.
Fire. The creature is set on fire for 3 rounds, suffering 1d4 fire damage at the start of each of their turns. A creature can spend an action to douse the flames, ending the effect.
Force. The creature is pushed backwards 5 feet in the opposite direction of the attack. This movement stacks with other effects that would cause forced movement.
Lightning. The creature is stunned for 1 round.
Necrotic. The creature becomes frightened of the creature who caused the effect for 3 rounds. If the creature has any food such as rations, they begin to spoil and are reduced by 1 day.
Piercing. The effect leaves a gaping wound in the creature, making further attacks easier. Attacks against the creature now crit on a roll of 19-20. If a creature already has an increased crit range, it is increased further by 1 against that creature. This effect ends when the creature regains any number of hit points.
Poison. The creature becomes poisoned for 3 rounds.
Psychic. The creature becomes confused for 1 round as if under the effect of the Confusion spell.
Radiant. The creature becomes blinded for 3 rounds.
Slashing. The creature begins bleeding, suffering 2 damage at the start of each of its turns until it regains any number of hit points.
Thunder. The creature becomes deafened for 3 rounds.