Have you ever made really dumb logic mistakes in your writing?

Oh, of course. That's where 75% of my plot holes lie. In the first draft of my story, I made the love interest's pet a polar bear (a genetically modified one, but still). Realized he would have been eaten long ago and changed it to a horse. Suits him much better than being eaten.

Also, that Spongebob moment was pure gold.

Does having the mad scientist use a machine that blew up three paragraphs ago count?

(Thank you, then-writers-group, for catching that one....)

Oh, holy smokes, yeah. Every novel I write has at least one in the first draft.

One time, MC#2 tries to cover the DNA evidence of a crime (ETA: not committed by him, he's trying to cover up MC#3's crime) by cutting himself and dripping his blood on the evidence before he throws it in a creek. No need; any DNA would be decomposed by the time someone fished it out (if they ever did--Nobody sees a pair of panties in a creek and says "Oh, I'll bet that's crime evidence. I better fish it out and run a DNA analysis."). I turned it into a moment for the MC#1 to call him out as being overly dramatic, which MC#2 definitely was. It was fun to make it work.

In another book, a major plot point revolves around the agronomist MC following a false lead by mistaking the crop in the background of a hostage picture to be one that only grows hundreds of miles away. Turns out, in real life that crop grows all over the place where the MC lived, and there was no way he would have made the mistake he made. It was only the author that made the mistake. In this case, the entire book ground to a halt. I needed him to follow the false lead so he could meet the people he needed to for the story to go where I wanted it to. I still haven't fixed it.

Oh, let's see . . .

When I was a young teen, I wrote a spy story without understanding how spying works. The MMC and FMC headed out on their spy mission and stopped to kiss their mother goodbye. She said, "I have no idea what spies look like, but you look great."

The FMC was having an intense conversation while making bread, which I do have experience in. However, I was more focused on the dialogue than the background action, so she mixed the ingredients together, put them in the oven, then kneaded the result before leaving it on the counter to rise.

This is not to say that I haven't made more recent logical errors. I just . . . haven't found them yet . . .

When I was a kid, I wrote a story about a wild horse who lived on the beach. I knew firsthand sea water was salty and tasted awful. I knew if you drank too much sea water, you would die. I knew that animals didn't drink sea water, period. And what did I do? I wrote about how she was standing on the beach, drinking the sea water, and then suddenly heard a noise and lifted her head... I couldn't tell you a thing about the rest of that story, but I always remembered writing that opening scene, and how it fell onto the paper even after I deliberately told myself not to write it like that because it would be wrong.

One of my favorites was probably one of the Top 5 Best-Known Names in the Golden Age Mystery genre. A lot of the plot hinged on the fact that the victim was a hemophiliac, so that completely skewed the reconstruction of the murder timeline. But he wasn't just any hemophiliac--- he was, like, descended from Russian royalty that had fled during the revolution and was denied his rightful place in the world, and a chunk of the story dealt with his delusions of grandeur. Except-except-except--- hemophilia was introduced into the Romanov line via Queen Victoria's granddaughter, Alexandra. But the murder victim's supposed royal ancestor predated Alexandra's introduction into the family tree. I kept waiting for the characters to point out this flaw in his claim that would prove once and for all he was an imposter, although an honestly deluded one... and they never did, it was just a mistake on the writer's part.

Maybe she ages more slowly. Maybe it's Maybelline.