Venom, and my latest addition and personal favorite...Robin!
I can see Iron-Man doing this type of thing because he's a cocky asshole and showing up to Gotham City in a suit fashioned after Robin would piss Batman off in just the right way.
This minifigure is made by Elephant, which in the past has had some lower quality figures from what I have seen online, but seems to be doing just fine with their recent Iron-Man minifigures (at least concerning the Venom and Robin I own.)
Like with Iron-Venom, Iron-Robin came with a Jarvis arm build, but I didn't bother with building it this time around.
Under the hood is Tony Stark's snarling visage. I need to add in a Robin heapiece to make this into a Robin in an Iron suit minifigure (as I envision it). I also need to get me the Iron-Batman suit!