Smiting

Smiting is an ability inherent in all angels, allowing them to kill anything with a single touch. When angel places their hand on whom ever they wish to smite, the being face becomes consumed with light, leaving their eye-sockets burned out and liquefying their insides. However, Alastair was able to deflect Castiel's attempts to smite him in 4.10 Heaven and Hell and due to Leviathans predating angels, they appeared to be immune as well.

The Host of Heaven is also able to combine their powers into one single focused blast of energy. Smiting of this magnitude has such power that it can cause fallout which will poison the areas for miles from ground zero. This fallout can negatively effect humans that approach ground zero, inducing a smiting sickness, which can lead to death (or in the case of Lot's wife, turn into a pillar of salt). Smiting of this magnitude rarely happens on Earth, with the destruction of Sodom and Gomorrah being the only known mass smiting before the arrival of Amara.

Episodes

4.01 Lazarus Rising

While Sam is staking out Johnny Mac's Diner after Dean's earlier demon confrontation. Sam sneaks into the darkened diner, as he creeps in quietly, he sees the cook from earlier face-down on the floor, his hands bloody. Sam crouches and turns the man over, revealing his eyes burned out and drying blood caked on his cheeks. He soon gets tackled from behind by the demon waitress, they trade blows before Sam eventually shoves her away, revealing that she too has empty, burned out eye sockets and blood trickling down her face.

4.10 Heaven and Hell

When Alastair his demons try to take Anna away, Castiel and Uriel arrive. While Uriel smite the subordinate demons. Castiel attempts to smite Alastair, but is shocked to find he has no effect on the demon.

11.09 O Brother Where Art Thou?

When the angels decide to take the fight to Amara. The Head Angel is able to locate Amara, and with two others by his side, he demands that Amara surrender to the judgement of Heaven, telling her if she resists each and every angel in the skies will smite her, in a single unified blow. Amara in turn kills the three angels one by one, and when the skies began to crack with thunder and lighting and clouds begin darken to swirl, Amara gives one last look of concern to Dean before she sends him away and takes the angel smiting head on with her arms wide open as a blaze of holy light envelops her and the ground explodes.

11.22 We Happy Few

While discussing how to defeat Amara with God and Lucifer, Dean remembers that the angels mass-smiting actually hurt Amara. As a result, Lucifer and Castiel recruit the angels to perform another mass-smiting to help defeat her. After five witches hit Amara with a magical attack, Heaven sends down another mass-smiting which Amara once again takes without resistance. Though not having an effect on her to the same degree as the first time, Amara is weakened by the blast, allowing a mass demon attack and a strike by Lucifer with his spear to defeat her.