That twin towers part reminded me of something similar that happened to me:

A buddy and I were camping, and we had both taken a little bit of acid. We did some wandering around during the come-up, then as it got dark we built a fire and spent the rest of the trip watching the flames and embers.

As the fire died down, one of the logs in the fire somewhat resembled the back of a dismembered knee in a funeral pyre. My friend and I were just kinda lost in thought, neither of us were speaking, just staring at the fire. I blurted out in a somewhat serious tone "BURNING JEW BODIES" while staring at the log. He kept staring for a few moments, then looked at me like "dude, what the fuck?" Then we both burst out laughing.

I could tell we both could see the resemblance of that log to a dismembered knee, and knew he'd make the same connection that I did. Then we both kinda sat there, lost in thought again, with the horrific realization that people actually have killed and burned one another, and that was a heavy, heavy thing to grasp. It was almost like peaking back into the dark history of man.

After a few moments, he said "dude, now I can't fucking unsee that, and now whenever I see a fire I'm going to think of burning jew bodies, which is beyond fucked up. Not to mention, those people over there probably heard you say that then heard us bust out laughing, so now they probably think were some weird fucking antisemites."

It's been a good year or more since that trip, and even still the phrase "burning jew bodies" has become some sick twisted inside joke between us. One of us will say it out of the blue, then burst out laughing thinking back to that trip.

TL;DR: My friend and I, even though we're not racist, will burst out laughing at the phrase "burning jew bodies" because of something weird we saw while on acid. I know it's fucked up to laugh at that, but sometimes, that's the only thing you can do to make sense of something so horrific and senseless.