You can be threatened or sued for pretty much anything - if they care, are bought by someone who cares (ie Disney) or in the future start caring then you might

You can be threatened or sued for pretty much anything - if they care, are bought by someone who cares (ie Disney) or in the future start caring then you might be sued. Whether it goes anywhere or whether you win is a different matter. Trademarks are based on a class of product or thing however (see eg the goods and services listing on https://trademarks.justia.com/875/27/iron-87527652.html https://trademarks.justia.com/875/27/iron-87527652.html - one of a bunch of iron man trademarks), so if there's no confusion/it's not a category that they have trademarked, then your odds are better.