Ragnaros the Firelord
Can't attack. At the end of your turn, deal 8 damage to a random enemy.
Ragnaros was summoned by the Dark Iron dwarves, who were eventually enslaved by the Firelord. Summoning Ragnaros often doesnt work out the way you want it to.
How to get:Obtained via crafting. Costs: 1600
How to get Gold:Obtained via crafting. Costs: 3200