Shatter

Shatter is a common mage spell card, from the Whispers of the Old Gods set.

Strategy
This card has obvious synergy with decks involving Freeze effects, such as Freeze Mage. It is most efficiently combined with AoE Freeze effects like Blizzard, allowing the mage to remove a single minion that survived the former spell's weaker damage. At best it can be used with Freezing Potion for a 2-mana hard removal.

Unfortunately, its inability to function without synergy makes this card ineffective in most cases.

Snap Freeze is a strictly superior version of this card.

Lore
In World of Warcraft, is a passive  ability, gained at level 16. It multiplies the critical strike chance of all of the mage's spells against frozen targets by 1.5 and adds another 50% chance.

Shatter is a critical component in the Frost mage arsenal, adding synergy and burst damage with their many freezing spells, such as Frost Bolt, Frost Nova and Ice Lance.

Trivia

 * Shatter was originally designed for the Curse of Naxxramas adventure as the mage reward. It was originally a 4-mana spell with the effect "Destroy all Frozen minions".
 * On various occasions in 2017 and 2018, then-Game Director Ben Brode and Lead Producer Yong Woo cited Shatter as an example of a card that could potentially be added to the Classic set as a replacement for Classic cards that had been moved to the Hall of Fame. This is because the card's effect is simple and easy to understand, its power level is low enough that it would be unlikely to have a large impact on the meta, and it helps establish the mage class' identity of having a major focus on Freeze effects.   However, following the creation of entirely new Classic cards starting with patch 12.4.0.27405 in November of 2018, this idea has likely been abandoned.
 * The flavor text is a reference to a lyric in the 2003 Outkast song "Hey Ya," in which singer Andre 3000 proclaims "What's cooler than being cool?" to which the response is "Ice cold!"

Patch changes

 * Frost spell school added.
 * Added.