An It's Always Sunny Rehearsal Mistake Gave Frank One Of His Most Famous Lines

"It's Always Sunny in Philadelphia" is a wildly quotable show, chock-full of hilarious one-off lines that are funny even without context. Each member of the gang has loads of great quotes, but the one with probably the most amazing, ridiculous lines is Frank Reynolds (Danny DeVito). The former business magnate has lived a wild life, and he says the most absurd things pretty regularly. (His insane levels of drug and alcohol consumption probably have something to do with it, too.) There's also DeVito's accent as Frank, which ranges between that of his native New Jersey and something sort of like a Philly accent, making everything Frank says sound pretty amazing. DeVito contributed more than just his unique Frank accent and line delivery to one of his most famous lines, too, by switching up some words. 

On an episode of the "Always Sunny Podcast" covering the season 5 episode "The D.E.N.N.I.S. System," the series' stars and creators Charlie Day, Glenn Howerton, and Rob McElhenney discussed one of the series' most frequently re-quoted lines, revealing that it was all because DeVito messed up his line in rehearsal and the accidental version was simply funnier. 

He dropped his monster condom

On the podcast episode, where the boys were joined by guest star (and Glenn's wife) Jill Latiano Howerton and writer/producer Megan Ganz, the subject of Frank's amazing line about his "monster condom" came up, sending them down memory lane. Glenn Howerton, who plays Dennis, explained that DeVito "screwed it up in rehearsal or something," and that it was "one of those, like, Danny accidents that we're like, 'Yes, that.'" Instead of saying, "I dropped my Magnum condom for my monster dong," Frank says the reverse, and it's truly hilarious because it's unexpected and still kind of works. The cast of "It's Always Sunny" frequently improvise on-set, playing around with the written scripts a little bit if there's something that works better than what's on the page, and apparently they'll do a bit of that in rehearsal as well!

Howerton went on to remind them of another time when a guest actor on the season 2 episode "Hundred Dollar Baby" said "don't get your panties in an uproar" on accident instead of "don't get your panties in a wad," cracking up the cast and making them change the line for the final edit. Sometimes, mistakes can be comedy gold, and the team behind "It's Always Sunny" knows just how to embrace those happy accidents. By knowing when to play fast and loose with their dialogue and when to tighten things up, they've managed to keep the series fresh season after season. Thank goodness for funny flubs.