It works a lot like Tracking. When you play it, all of the Secrets and weapons in both decks will be laid out on the screen for you to look at (you'll only see one copy of each, even if there are more copies in the deck). If you activate the Combo, you can then select one to gain a copy of.
Response to Balance Concerns:
I definitely realize that in some situations this card would get absurdly good value... But that's only in some situations. After all, there are three classes (Druid, Priest, and Warlock) that have no Secrets or weapons.
Now consider that, if you're running this card, you probably want there to be at least one weapon in your own deck that you can pull to prevent its Combo effect from being useless in a whole third of possible match-ups. Only now that you already have your favorite Rogue weapon in your deck, the card is also a lot less useful against other Rogues. Now factor in that Rogue weapons themselves tend to be rather meh, which is why so few people run any of them, so really what you're hoping to do with this is take something more useful from your opponent, especially since this only copies a card, so it doesn't help thin your deck at all.
Only some variations of Shaman run weapons, so that leaves only 4 classes that this is actually consistently good against: Hunter, Paladin, Mage, and Warrior. When you start looking at the bigger picture like that, it becomes more clear how, even though Espionage can be really awesome in some match-ups, it's really underwhelming in others. It's situational, similar to Kezan Mystic and other tech cards in that regard, that are allowed to be crazy awesome sometimes because of how bad they can be other times.
Basically, like an inverse mind control, only that you give a minion to your enemy, and you win a coin.
Should be really niche and almost useless, but it is an interesting mechanic, which you could use to weaken your enemy, for example cards with perjudicial deathrattles, annoying efects, or global effects which you need to stay on the board.
The most obvious use would be as an effective combo in mill rogue: you summon a fel reaver and then you give it to your opponent, use millions of cheap spells like spare parts, preparation, backstab, and even closing with sap. Effectively destroying 6+ cards on your opponent deck.
This is designed as a weapon that starts weak and buffs itself. As long as you can continually trade with this weapon, it becomes like a slower Truesilver Champion with one more durability. Also, the Claws do interact with Shield Slam, so that's fun. At two damage, more than likely you have a way to trigger it's effect through minion trading.
This sword is so rare they should have created a "Mad high level frustration farm-rarity" just for it.
Just a clarification: the effect occur when you deal damage (both to Heroes and to minions), so if you attack a minion with Divine Shield you won't get your Shadow Bolt 'cuz you aren't doing any damage; also, if you Blade Flurry you won't get any Shadow Bolt either, obviously considering the damage comes from the spell, not from the weapon.
Who wants 0 mana PreparationShadow Bolt? Could fit in the new control Rogue archetype Blizzard want to implement.
Rouge weapon that lets them get cheap spells [Which aid combos] over 2 turns, but is not very valuable to use with Flurry or to hit minions. Every class has useful Sub-2 mana spells. That interesting part comes from the possibility to buff the weapon's attack to have a chance to get better spells. Deadly makes it up to 4 mana. Oil makes it 5. Buccaneer or Barber makes it 3.
Costed 4 because it's effect is probobly stronger than Perdition's Blade but it has the same stats, and while it's effect is stronger it NEEDS to hit face.
With TGT releasing, I managed to get Anub'arak and Beneath the Grounds, and I've absolutely fallen in love with them. Therefore, I'm giving BtG to priest too. Because reasons.
"Warriors feel very stolen from"
The card can get the same weapons as Blingtron 3000
The upgrade is the same as the warrior spell Upgrade! (+1 attack and +1 durability)
Check out some Super Smash Brothers Cards
It works a lot like Tracking. When you play it, all of the Secrets and weapons in both decks will be laid out on the screen for you to look at (you'll only see one copy of each, even if there are more copies in the deck). If you activate the Combo, you can then select one to gain a copy of.
Response to Balance Concerns:
I definitely realize that in some situations this card would get absurdly good value... But that's only in some situations. After all, there are three classes (Druid, Priest, and Warlock) that have no Secrets or weapons.
Now consider that, if you're running this card, you probably want there to be at least one weapon in your own deck that you can pull to prevent its Combo effect from being useless in a whole third of possible match-ups. Only now that you already have your favorite Rogue weapon in your deck, the card is also a lot less useful against other Rogues. Now factor in that Rogue weapons themselves tend to be rather meh, which is why so few people run any of them, so really what you're hoping to do with this is take something more useful from your opponent, especially since this only copies a card, so it doesn't help thin your deck at all.
Only some variations of Shaman run weapons, so that leaves only 4 classes that this is actually consistently good against: Hunter, Paladin, Mage, and Warrior. When you start looking at the bigger picture like that, it becomes more clear how, even though Espionage can be really awesome in some match-ups, it's really underwhelming in others. It's situational, similar to Kezan Mystic and other tech cards in that regard, that are allowed to be crazy awesome sometimes because of how bad they can be other times.
"Come to the light side, we have cupcakes."
Here's my entry:
Basically, like an inverse mind control, only that you give a minion to your enemy, and you win a coin.
Should be really niche and almost useless, but it is an interesting mechanic, which you could use to weaken your enemy, for example cards with perjudicial deathrattles, annoying efects, or global effects which you need to stay on the board.
The most obvious use would be as an effective combo in mill rogue: you summon a fel reaver and then you give it to your opponent, use millions of cheap spells like spare parts, preparation, backstab, and even closing with sap. Effectively destroying 6+ cards on your opponent deck.
Edit: Also, doomsayer for easy board clear
The weapon feeds off Fire spells from you AND your opponent.
50% chance to get a Weapon with 3 attack or higher.
40% chance to get a Weapon with 3 durability or higher.
Examples of Fire spells from 6 classes : Flamestrike, Soulfire, Explosive Shot, Holy Fire, Lava Shock, Consecration.
Edit: Changed image host from Hearthcards to Imgur.
Vote for my Soulmancer class in Class Design Competition #3
Galavant Animation
For reference, Claw.
This is designed as a weapon that starts weak and buffs itself. As long as you can continually trade with this weapon, it becomes like a slower Truesilver Champion with one more durability. Also, the Claws do interact with Shield Slam, so that's fun. At two damage, more than likely you have a way to trigger it's effect through minion trading.
This sword is so rare they should have created a "Mad high level frustration farm-rarity" just for it.
Just a clarification: the effect occur when you deal damage (both to Heroes and to minions), so if you attack a minion with Divine Shield you won't get your Shadow Bolt 'cuz you aren't doing any damage; also, if you Blade Flurry you won't get any Shadow Bolt either, obviously considering the damage comes from the spell, not from the weapon.
Who wants 0 mana Preparation Shadow Bolt?
Could fit in the new control Rogue archetype Blizzard want to implement.
My submission for this week!
Rouge weapon that lets them get cheap spells [Which aid combos] over 2 turns, but is not very valuable to use with Flurry or to hit minions. Every class has useful Sub-2 mana spells. That interesting part comes from the possibility to buff the weapon's attack to have a chance to get better spells. Deadly makes it up to 4 mana. Oil makes it 5. Buccaneer or Barber makes it 3.
Costed 4 because it's effect is probobly stronger than Perdition's Blade but it has the same stats, and while it's effect is stronger it NEEDS to hit face.
Current Deck -http://www.hearthpwn.com/decks/240420-army-paladin - Token Paladin
Here is my card:
Hosted in Imgur now: http://i.imgur.com/n9yLFZY.png
Molten Core cards:
Flame Imp, Hellfire, Lava Shock, Lava Burst, Fireguard Destroyer, Flamewaker, Flamestrike, Fireball, Flame Lance, Core Rager, Molten Giant, Baron Geddon, Core Hound, Fire Elemental, The Beast, Druid of the Flame, Volcanic Lumberer, Magma Rager, Majordomo Executus, Ragnaros the Firelord, and Sulfuras.
"You miss 100% of the shots you don't take. - Wayne Gretzky"
-Michael Scott
Please vote for my card, Hulking Void Terror, in week 29! http://www.hearthpwn.com/forums/hearthstone-general/fan-creations/55403-weekly-card-design-competition-29-submission-topic?page=10#c145
This isn't even my final form!
Some say power is unnecessary, I proved them wrong.
Warning: may be sticky...
With TGT releasing, I managed to get Anub'arak and Beneath the Grounds, and I've absolutely fallen in love with them. Therefore, I'm giving BtG to priest too. Because reasons.