Quoting mari_ su ♡:" <blockquote><b>Quoting Jude ♥ JGL:</b>" Is.there a theme? I just did balloons"</blockquote> I probably should have mentioned that lol, Transformers is the theme."
I'm not sure but you could do clusters of balloons in yellow/ black/ gray or red/ black/ blue. For the main characters.
off topic but on the same theme as your son's b-day... transformers cake I made a few months back.