I think you've misunderstood, I'm only using “Iron Giant” as a descriptor, i.e. a point of common reference. The actual design is not a copy, as you can see from the image below:
Let me know what you think!
—Colin
If it looks close enough to the "Iron Giant" and you call it "Iron Giant," WB might see it as Iron Giant! You're even making it in the Art Deco style, much like the WB Iron Giant. You could also run into issues if it resembles any of their pre-production art (especially if it was published) or other intermediate designs from before the finished version. Call it "generic robot" and make it not resemble the Iron Giant (or any other big robot that's appeared in publicly-released media, unless that media is in the public domain), no sweat - but as it is, you could have problems.
You wouldn't argue that a cellphone has anything to do with "Star Wars," right? That didn't stop Motorola from paying Lucasfilm licensing fees for the rights to use the name "Droid" for their line of smartphones. One could have easily argued in court that it was a shortened form of the word "android," a word that predates the first-released Star Wars film by about fifty years. But they just didn't want the hassles of a potential lawsuit against them by a wealthy company - and they're Motorola, not some guy sitting in front of his computer with a drawing tablet in his lap.
Even if you were 100% legally in the right on this, would you have the resources to defend against a WB lawsuit? Better not to invite one in the first place. I'm only saying this because no one wants that headache.
Look around on this forum and on Kickstarter for information about a really cool (killed) deck design called "Bicycle Army Men." It's a very sad story. That deck's creator got all the way through KS, was successful meeting his goal with money to spare, spent a portion of his "profits" to pay for his wife's student loans - then got knocked on his ass by a lawsuit from the company that owns the rights to the toy "Army Men." Turns out they're not simply some cheap, generic plastic toy churned out by the bazillions in some Far East nation, but an actual piece of intellectual property owned by a US company.
The designer did the honorable thing in that he worked his ass off repaying his backers, but the money he spent on that and on lawyers trying to appease the company suing him must have been punishing, because he vanished from this forum, never made another deck, and the company he co-founded, Circle City Card Co., sold their IP to Gambler's Warehouse and disbanded. It's why GW reprinted the Bicycle Americana deck in green - they bought the rights to the art from CCCC, specifically from the Bicycle Army Men artist's partner (who had problems of his own with KS reward fulfillment on another deck). The Bicycle Army Men deck never saw the light of day, and never will.
You need to be as completely clear about your intellectual property as you can. If you make something completely original and your own, great. If you base your work on something you already own, great. If you base it on something that's clearly in the public domain, great. If you make something that another company might argue is theirs, especially if that company has much deeper pockets than you, you're really taking a chance. Even if you're completely in the right, even if their argument could be viewed by a judge as specious or without merit, you probably won't have enough resources to see that judge and have your day in court before you run out of cash, not to mention the emotional toll it would take. It sucks, but being in the right alone isn't always enough. All that, over a single joker...