I mean if that's the case anything is iconic, if we're going down that road.
A Halloween costume isn't enough to claim your work as a phenomenon and iconic but I'm sure others will quickly point out that I'm misguided.
It's kind of silly to quibble about the specific degree to which those words should apply as that's going to be subjective and difficult to articulate to any real degree. Like, OK, you don't think Halloween costumes qualify (and no, not anything gets used for Halloween costumes), but so what? His overall point should be obvious: he didn't anticipate that the movie would be so resonant that it would inspire people to dress up for Halloween, and now that it is, he's commenting on how it feels for it to reach that level of popularity.
"Wow my movie is so popular it's inspiring people to do thing and tag me on Instagram, that's cool but also kinda weird."
"Uh what makes you think your movie was popular at all bro, that's pretty
pretentious of you"
"Uh I literally just said the thing that makes me think that"
???