Damage shield

Damage shield refers to damage that is inflicted on an enemy after striking a player in combat.

There are two different type of damage shields:

"True" damage shields: These have a 100% chance to proc, but can only be triggered by melee attacks. The damage is not considered spell damage. Example: Druid's [Thorns].
Damage shields with procs: These do not necessarily trigger off every attack. However, they are not limited to melee attacks (unless specifically mentioned otherwise). The damage inflicted is considered spell damage. Example: [Girdle of Reprisal].

Equipment

Chest

[Demon Forged Breastplate] Equip: When struck has a 3% chance of stealing 120 life from the attacker over 4 sec. This item is crafted by a Blacksmiths with 285 skill.

Cloaks

[Cloak of Flames] - Equip: Deals 5 Fire damage to anyone who strikes you with a melee attack.

Gloves

[Razor Gauntlets] - Equip: When struck in combat inflicts 3 Arcane damage to the attacker. This item drops from Alzzin the Wildshaper in Dire Maul East.

Shields

[Crest of Retribution] - Equip: Deals 5 to 35 damage every time you block. This item drops off Ramstein the Gorger in Stratholme.
[Force Reactive Disk] - Equip: When the shield blocks it releases an electrical charge that damages all nearby enemies. This also has a chance of damaging the shield (deals 30-40 damage to enemies in a 10 yard radius each block). The item is crafted by Engineers with a skill level of 300.
[Drillborer Disk] - Equip: When struck in combat inflicts 3 Arcane damage to the attacker. This item drops from Garr in Molten Core.
[Petrified Lichen Guard] - Afflicts your attacker with deadly poison spores each time you block. The item can be bought from the Sporeggar Quartermaster Mycah for 15 Glowcaps, once you are Template:Honored with the Sporeggar faction.
[Vile Protector] - When struck in combat has a 1% chance of inflicting 105 to 175 Shadow damage to the attacker. Quest rewards from [38] Compendium of the Fallen.

Waist

[Girdle of Reprisal] - Equip: 1% chance when struck in combat of dealing 75 to 125 Shadow damage to the attacker. Quest reward from [43] Ledger from Tanaris.

One handed

[Gahz'rilla Fang] - Chance On Hit: Surrounds you with electricity, dealing 10 Nature damage to any who strike you for 15 seconds. This item drops from the summoned boss Gahz'rilla in Zul'Farrak in Tanaris.

Two handed

[Sulfuras, Hand of Ragnaros] - Equip: Deals 5 Fire damage to anyone who strikes you with a melee attack.

Necklaces

Rings

[Naglering] - Equip: When struck in combat inflicts 3 Arcane damage to the attacker. This item drops from Golem Lord Argelmach in Blackrock Depths.

Trinkets

[Darkmoon Card: Vengeance] - You have a 10% chance when hit by an attack or harmful spell to deal 95 to 115 holy damage to your attacker. This item can be obtained by collecting Darkmoon Faire Furies cards and assembling them into a [Furies Deck].
[Heart of the Scale] - Use: Increases Fire Resistance by 20 and deals 20 Fire damage to anyone who strikes you with a melee attack for 5 minutes. 30 minute cooldown. This item drops from Overlord Wyrmthalak in Lower Blackrock Spire.
[Fetish of Chitinous Spikes] - Use: Spikes sprout from you causing 25 Nature damage to attackers when hit. Lasts 30 seconds. 3 minute cooldown. This item drops from Buru the Gorger in the Ruins of Ahn'Qiraj.
[Essence of the Pure Flame] - Equip: When struck in combat inflicts 13 Fire damage to the attacker. This item drops from Ragnaros, final boss of the Molten Core.

Blacksmithing

[Iron Shield Spike] - Attaches to shield, deals 8 - 12 damage when you block.
[Mithril Shield Spike] - Attaches to shield, deals 16 - 20 damage when you block.
[Thorium Shield Spike] - Attaches to shield, deals 20 - 30 damage when you block.
[Felsteel Shield Spike] - Attaches to shield, deals 26 - 38 damage when you block.

Consumables

[Crystal Spire] - Use: A crystal shield surrounds the friendly target, doing 12 damage to anyone who hits her. Lasts 10 minutes. (Cystal Spire does not stack with thorns). This item is a quest reward from [53] Crystal Spire
[Gift of Arthas] - Use: Increases resistance to shadow by 10. If an enemy strikes the imbiber, the attacker has a 30% chance of being inflicted with disease that increases their damage taken by 8 for 3 minutes. Lasts for 30 minutes. This item is made by Alchemists with a skill level of 240.

Druid: [Thorns] - Thorns sprout from the friendly target, causing X Nature damage to attackers when hit. Lasts 10 min.
Paladin: [Retribution Aura] - Causes X Holy damage to any creature that strikes a party member within 30 yards.
Warlock: Imp's [Fire Shield] - Anything that attacks a party member takes X fire damage. Lasts 3 min.

Priest: Shadowguard - The caster is surrounded by shadows. When a spell, melee or ranged attack hits the caster, the attacker will be struck for 130 Shadow damage.
Shaman: [Lightning Shield] - The caster is surrounded by 3 balls of lightning. When a spell, melee or ranged attack hits the caster, the attacker will be struck for 287 Nature damage.