Cogmaster is a common neutral minion card that belongs to the "Goblins vs. Gnomes" set, which was released on 08.12.2014 and is one of initially 123 cards. The artist of this card was Trent Kaniuga, who also made 21 other artworks for Hearthstone.
The flavor text of the card is the following: After a while, you don't see the cogs and sprockets. All you see is a robot, a spider tank, a deathray...
The card is easy to memorize with 96.36% of correct quiz questions.