While Riva joked to NPR in 2009 that it was pretty funny telling his kids about the custom toilet, in actuality the bit of plumbing represented a much darker turn for Tony Stark. “Tropic Thunder” screenwriter Justin Theroux was brought in to write an adaptation of Marvel Comics’ “Demon in a Bottle” storyline, which sees Tony struggle with his alcoholism and finally hit rock bottom. It’s harrowing stuff that nevertheless gives the character more depth and pathos, but in the end it was just deemed too intense for families and would have been a bummer for the box office. As Theroux once told UGO (via MTV):

“It’s just a great, gritty storyline. It doesn’t transfer to film. We didn’t want to be the ‘Leaving Las Vegas’ version of ‘Iron Man 2.’ Even just a little bit of that can completely dominate the story.”

“Demon in a Bottle” sees Tony eventually overcoming his alcoholism and getting clean, but the folks at Marvel Studios weren’t willing to go there when “Iron Man 2” was already taking quite a few risks. It’s entirely possible that taking the already character-driven sequel into a darker direction would have alienated audiences and really hurt the MCU right as it was getting into its stride, much as people love their superheroes.