Dennis reveals he has a baby from his Wade Boggs layover in North Dakota, and everyone offers a solution for how to get him out of this jam.
- Charlie Day as Charlie Kelly
- Glenn Howerton as Dennis Reynolds
- Rob McElhenney as Mac
- Kaitlin Olson as Dee Reynolds
- Danny DeVito as Frank Reynolds
- Jaxon Korossy as Brian Jr. #1
- Lucas Korossy as Brian Jr. #2
- The layover in North Dakota that led to Dennis becoming a father is a result of the events of the Season 10 episode "The Gang Beats Boggs."
- Charlie finally bangs The Waitress, having convinced her it's the only way she could have a baby. As soon as she starts becoming realistic about their situation, he flees and claims her numerous calls to him are her "stalking" him.
- When Charlie is sleeping on the couch with Dee, he tells her not to "try and bang him again".
- Mac has refurnished his and Dennis' apartment down to every single knick-knack, with the exception of his old room being a "home gym" (just the Ass Pounder 4000 and some towels in an empty room), planning on himself and Dennis sharing Dennis' old room.
- A poster for Thunder Gun 2: Still Gunnin' can be seen on the street.
- Dee is happy to have her apartment back to herself, suggesting a year has passed since "Mac and Dennis Move to the Suburbs", as Old
BlackMan is no longer sleeping in her bed.
- When the Gang minus Dennis are celebrating, each displays their signature dance move: Charlie's Butt Butt Dance, Dee's inflatable tube man, Mac's elbow-heavy karate dance, and Frank's "move".
- After Dennis' exit, the rest of the Gang quickly blow up his Range Rover with the RPG Mac got him for Valentine's Day in "The Gang Tends Bar".
- Dennis first pretended to be Brian LeFevre in the episode "Frank's Back In Business." The real Brian LeFevre was a Canadian businessman who left his wallet in the bar, and was stabbed to death by a homeless man in the alley behind Paddy's. Dee played his wife Prudence, changed to his sister here. Mac starts to identify himself as Vic Vinegar, the LeFevres' bodyguard, but Dennis stops him.
- Mac and Dennis' apartment burned down in the Season 9 finale "The Gang Squashes Their Beefs", and they moved in with Dee at that point. Their apartment was repaired in the Season 10 finale "Ass Kickers United: Mac and Charlie Join a Cult", but burned down again at the end of that episode.
- This is the first season finale that ends with a cliffhanger. It is not certain that Dennis will return: around the time this episode first air, Glenn Howerton stated in an interview that he wasn't certain he would be returning to the show.  Previously the second seaon's finale, "Dennis and Dee Get a New Dad", ended on the minor cliffhanger of Charlie discovering that Frank may be his father, but it was not presented with the same weight of a traditional cliffhanger.
- Howerton later clarified that he would be continuing work on the show, but left Dennis' fate undeclared
- This episode leaves Mac once again as a possible "odd man out", this time with babies/parenthood: Frank believed he fathered Dennis and Dee (and is likely Charlie's real father), Dee has given birth as a surrogate mother, and this episode presents Dennis' baby and Charlie possibly impregnating the Waitress. Though Mandy offers Mac and Dennis a two-dads situation, it never comes into play. Previously, Mac was the odd man out in regards to the Reynolds family, until he was allegedly adopted by Frank for "The Gang Goes on Family Fight".
- The Waitress appeared last in Season 11's "Frank Falls Out the Window", 17 episodes ago; this is the longest gap of time between episodes featuring her (although she is mentioned in "The Gang Tends Bar", after Charlie mentions that his song for Dee is derivative of one he wrote for the Waitress).
- The Waitress claims that sex with Charlie was "actually kind of amazing"; he likely utilized what Tatiana taught him about sex while the Gang is at the Poconos. (The Gang Hits the Slopes)
|—||“Look, why? You won't ever tell me why. You just say no, and you won't give me a shot. I don't understand what's so terrible about me.”|
|“What's so great about me, Charlie? What's wrong with you? Why are you so obsessed with me? I mean, you said it yourself, I'm a mess. So why don't you just go find somebody better?”||—|
|—||“.. well. 'Cause there is no one better. And.. I love you.”|
|—||“God! She's calling me again! It's like she's totally stalking me! Dee, what do I do here!?”|
|“You have been stalking that woman for 15 years, now she's finally showing you some attention and you don't like it?”||—|
- ↑ http://uproxx.com/sepinwall/its-always-sunny-in-philadelphia-finale-glenn-howerton-leaving-dennis/
- ↑ https://twitter.com/GlennHowerton/status/957318213292892160
|Season 12 Episodes|
|1. "The Gang Turns Black"|
2. "The Gang Goes to a Water Park"
3. "Old Lady House: A Situation Comedy"
4. "Wolf Cola: A Public Relations Nightmare"
5. "Making Dennis Reynolds a Murderer"
|6. "Hero or Hate Crime?"|
8. "The Gang Tends Bar"
9. "A Cricket's Tale"
10. "Dennis' Double Life"