The Bachelor Party Corrosion

"The Bachelor Party Corrosion" is the third episode of the ninth season of the sitcom The Big Bang Theory. The episode will air on Monday, October 5, 2015.

Summary
The girls throw Penny a mini-bachelorette party. Penny calls her Dad about getting married and Amy calls her mother about breaking up with Sheldon. The guys take Leonard to Mexico for a bachelor party weekend and can't change their tire when they have a flat.

Extended Plot
While Sheldon and Leonard are fixing lunch in Apartment 4A, Leonard offers up a fun fact about mustard although Sheldon already knows about it's component that can be used to ward off caterpillars. Raj and Howard enter Apartment 4A supposed to go see a movie. Instead since they had not been able to throw his a bachelor party due to him eloping, they are going to kidnap him and take him to an unknown destination to celebrate. Sheldon complains that their kidnapping is missing a blindfold, duct tape and ransom call. After that Leonard is ready to leave immediately. Penny already packed his bag AND Sheldon is coming too. He asks how they are going to make him come so they kidnap him; blindfold and duct tape included.

Driving down the interstate, Sheldon is again complaining about being taken against his will into a hippie's mobile sex dungeon. Howard hints that their something very special about this van. Sheldon asks if it runs on syphilis. The van they are using once belonged to Richard Feynman, one of Sheldon’s favorite physicists. Both Sheldon and Leonard get excited. Leonard suggests about all the cute grad students he picked up with the van. Sheldon is sure that they all talked physics together. Leonard asks where they are going. Raj hints that they have spicy food and you can get diarrhea there. First guess, India. Second guess, Raj's apartment. According to Howard they are heading to Meh-i-co. Sheldon tells Leonard not be fooled. He is from Texas and Meh-i-co is Spanish for Mexico. Raj wonders what problems he has with where they're going. Mariachi bands, wild dogs and beans with little worms in them that jump around. Howard tells him to settle down. The theme of the trip is to go to Mexico in Richard Feynman's van to stay in the house that Richard Feynman's house bought with the money he was given for his Nobel Prize. "Viva la Imodium," shouts Sheldon.

In apartment 4B, Bernadette is trying to get Penny to go to a strip club since the boys are off on a bachelor weekend. Penny quips that if she wants to see a naked man dancing, all she has to do is flush the toilet while Leonard is in the shower. Amy joins them, the posse still lives, bringing some cookies for the mini-bacelorette party. The cookies are shaped like penises with gummy worms for veins, circumcised and uncircumcised. As they boys are getting ready to cross the border, Bernadette hopes the guys don’t get too wild and crazy. Penny tells the world to watch their daughters or Sheldon may spend the night explaining NAFTA to them which did happen to Amy.

Sheldon finds out the limits that US Customs have on returning with DVDs, CDs and VHS tapes. There could be some VHS tapes leftover in a van that old. Especially Jane Fonda work out tapes. Also Sheldon wonders if everyone has their yellow fever shots. He got one just to go to EPCOT.

The girls discussed married life with Penny who has a husband who has not yet moved out of his apartment. He does sleep there at night; however, it is only time before Sheldon has a nightmare and finds the pile of pillows in Leonard's bed. Bernadette asks Amy about her single life. She claims to be focusing on herself and is considering a wardrobe change. The girls get excited; however, she decided to not change herself just because of a man. Penny tells her that it's not uncommon for a woman to get a makeover after a breakup. Amy is considering maybe changing one thing. Your glasses. Your sweater. Your hair. Your shoes. No, she wants her ears pierced. She never got it done because her mother thought that it was for whores, pirates and genies. Also had a clause in their Relationship Agreement forbidding cosmetic surgery unless it's to look like a Klingon. Amy wants to get it done elsewhere, but Penny can do it with a needle and an ice cube. Amy is not sure. Penny begs her that she will be gentle and to let her take her ear virginity. Bernadette thinks that the party is getting real weird.

On their way to Mexico, Sheldon tells Howard to watch his speed since they have it in for tourists. Howard dismisses it saying that if they get caught, they'll put Raj behind the wheel in a Sombrero. Raj asks him how many races he can insult in a single breath. He never watched the Olympics with Howard. Leonard compares that it's like riding around in the Batmobile if Batman was a physicist. They all hope that Feynman's mojo will rub off on them inspiring them to greatness. Sheldon doesn't believe in a lot of magical charms; however, sitting in Feynman's butt print does get his creative juices flowing. Suddenly they get a flat tire and Sheldon is worried that they are being shot at by bandits and may end up in a Mexican factory making Bart Simpson pinatas. Sheldon then again says that he is getting too old for this crud.

While Penny finishes up with Amy's ears, Bernadette notes that Amy hasn't changed her Facebook status. Amy agrees that she should let her Facebook friends know that. She tells Penny that she is no longer in a relationship with Sheldon. Penny hasn't yet changed hers since she hasn't yet told her parents that she is married. Her father wanted a father/daughter dance at her wedding. He didn't get to do it at her sister's wedding because her water broke. Penny figures her Dad isn’t getting any younger so she’ll just wait until he get remember things she'll tell him that it was magical.

Their van has a flat tire and Howard is trying to fix it. He learned that skill so that he could change the tires of damsels in distress (Meet women). Sheldon is trying to find and stay away from scorpions. There's your damsel. Howard can't get the last lug nut off. Raj wonders if he is turning it the right way and tries it himself. It doesn't turn the opposite way.

As Amy admires her pierced ears, she remarks that if her mother saw her now she would lock her in "The Sin Closet". Penny could see how they were not real close. Bernadette adds that at least she would have told her if she had gotten married. She adds that they would like to know since they love Leonard. Penny agrees to call them. They both think that Amy has told her mother about Sheldon, but also she hasn't. Penny gets annoyed that Amy insists she call home and told her family that she broke up with Sheldon. She calls her Dad and tells him that she married Leonard last week on the spur of the moment and is sorry that she didn't tell him. He is glad that she is happy. He understands that it is hard to tell someone somehting that you think is going to upset them. Penny calls him the best Dad ever. He replies for her to hold that thought. Her father accidently ran over her pet pig Moondance twelve months ago. And he didn't tell her? He notes that the apple doesn’t fall far from the tree. Bernadette tells Amy that no it's her turn.

All the guys are pushing on the lug trying to turn it. Raj is doing LaMaze to help push. Howard figures that he is pushing with his uterus. Leonard just considers this a physics problem. Sheldon quotes Archimedes where if he had a long enough lever, he could move the world. As they guys think about materials to build one, Sheldon says first they must decide to pronounce it lee-ver or leh-ver. Sheldon insists that its lee-ver since they are not going to rolls up their sl-eh-ves. Leonard says they’re going to be there for ee-ver.

Penny thanks the girls for making her make the call because before in her mind her pet pig was alive and rolling around in the mud. Now it's illegally buried in the backyard next to her great-grandmother. Bernie wonders why they didn't eat him. Moondance was a beloved member of her family. Now it's Amy's turn. Amy says to do it later because she is depressed about Penny's pig. And a little hungry. FIrst Amy fakes trying to dial and then she gets her mother, but makes stalling with small talk, Penny grabs the phone and tells her Mom about Sheldon, the ear piercing and the penis cookies. Penny then hands back the phone because her mother wants to talk to her.

Still working on the lug nut, Howard is hanging from a lever made out of a stop sign and pole. Then they muse about Star Trek phasers, Superman's heat vision, Green Lantern's ring and the Hulk, who might not get across the border with his temper. Leonard tells them that even though having the Avengers help them it a viable idea; they are scientists and should be able to use real science. Percussive shock, they keep hammering at the lug with the rhythm inspiring them to sing "We Will Rock You. Sheldon gets excited and breaks into a tenor doing the chorus. The curse of his identic memory. Thermal expansion, they try and heat up the lug with a torita chip. Sheldon is afraid the cooking chip would attract animals. Accelerated corrosion, using burning salsa and two electrodes, he hopes to corrode it off. Sheldon considers his idea innovative and doesn't feel he gives his M.I.T. education enough credit. Howard saw it on Myth Busters. Exothemic Reaction, using rust and aluminum they make some thermite to melt it off.  Howard says that the lug nut put up a good fight, but met his match as he lites the match. Next they are standing next to the van in glorious flames. first they wonder how various superheroes would tackle it. After applying scientific principles, Howard sets fire to some iron shavings to burn it off and ends up setting the van on fire. Raj notes that the lug nut is finally off.

Finally a filthy Sheldon and Leonard and coming up the stairs as they meet Penny going down with their laundry. Leonard mentions that they had a flat and couldn't get it off. Penny mentions that she pierced Amy's ears and her mother had Amy sit in Penny's closet. Sheldon told her that they blew up the van. Penny's pig was killed by her father's tractor. Leonard says that he had to spend the weekend in Mexico with Sheldon. Penny tells Leonard that he wins.

Summary by [] Trinabeana78

Critics
To be entered.

Trivia

 * First appearance of Wyatt since "The Boyfriend Complexity" (S4E9).
 * Following Kaley Cuoco's divorce from Ryan Sweeting in 2015, her name in the original credits was reverted to its original billing in this episode.
 * Similar to "The Focus Attenuation" (S8E5), Penny is the only one to share any scenes with any of the guys.
 * Amy's mother used to lock her in "The Sin Closet" when she was bad sounding like 's mother. She does not appear in this episode.
 * Amy hasn't seem to still close the door on her and Sheldon yet (didn't change her Facebook status to "single").
 * It is the second trip the boys had taken and ended up returning in another vehicle. The first one was in "The Bakersfield Expedition" episode when Leonard's car was stolen.

Quotes
* Penny: If I wanna see a naked man dance around, all I have to do is flush the toilet while Leonard's in the shower.

* (To Amy, stroking her ear) Penny: Come on, let me take your ear virginity.

* Bernadette: This party's weird.