It is

I read it to see if it was really that bad, like, surely this is a 'what if' or something, right? It has to just be a weird one panel thing, or something with a proper explanation like 'this is all a dream Margot Robbie had after eating cheap Mexican food'... right?

No.

This is a legitimate comic published by DC in which Poison Ivy farts in front of Harley, Harley tries to convince that there's no shame in farting, in fact if anything, it's something to be PROUD of, to do in front of as many people as you possibly can. This leads to a museum exhibit mentioning the letters of James Joyce (who was himself quite infamously into farting), and basically has Harley get cursed to be incapable of stopping herself from farting non-stop, while battling a character named 'Dutch Oven', but she can't defeat her because Harely's farts keep blowing her cover

I swear to god this is all what actually happens in the issue. I genuinely couldn't believe what I was reading. By the end I wanted to fucking shoot myself. I challenge people to read this issue, because however bad you think it can get, I promise you, it gets worse.