The Goblin Little Wizard hero has a special attack of range 1, damage 50 for each hero within 3 leagues. It comes with a risk of returning heroes within 3 leagues to their decks. The card costs 300 gold to deploy and the attack costs 6 mana.
What’s the purpose of this card? The attack power is underwhelming for its cost (I would expect a typical case would be 3 or 4 other heroes around, for 150 - 200 damage) and comes with the risk of pulling the other hero cards off the map.
You’ll find when you start to have very big stacks, especially in large multiplayer games that he will become very powerful.
Indeed, as Jay says, the Little Wizard is one of the most powerful combat units in the whole game! In addition to moving quickly and doing tons of damage, you may also notice that when he does return heroes to the deck, he refunds the player the gold that card cost to play. So if you keep him close to your Spider Pennons, you can re-deploy the returned cards right away, for free—or even for a profit, if you have a Dealer or ten on the board already…