The Maternal Combustion

Not to be confused with The Maternal Capacitance or The Maternal Congruence.

"The Maternal Combustion" is the twenty-third episode and penultimate episode of the eighth season of the sitcom The Big Bang Theory. The episode aired on Thursday, April 30, 2015.

Summary
While both Sheldon and Leonard's mothers visit to see their sons get an award, Bernadette wants more help around their new home from Raj, Howard and Stuart.

Extended Plot
While setting up, Leonard, Sheldon, Penny and Amy are discussing the upcoming the visits of the guy's s to see them get an award. Leonard knows when his mother reaches California by feeling a disturbance in. Sheldon is preparing a bowl of for his mother. If Amy asks for, then he calls them a "bouquet of severed plant ". Sheldon did get her a rotting that produced s for. Penny wonders if she should get something for Beverly since she is not that excited about her with Leonard. Leonard suggests her getting a overnight, though Penny points out that it did not work for him and his mother. Will the two different get along? One is brilliant while the other is sweet and simple according to Sheldon who compares it to his relationship with Leonard.

Sheldon is having with his mother who is proud of both of the, but can't understand the  they wrote about understanding the  as an. And the saving the world with an  is nonsense? Sheldon wants his mother to keep the babble down when talking to the brilliant  and woman of  Dr. Beverly Hofstadter. Mary wants to know if Sheldon is ashamed of her. Sheldon does love her, but is embarrassed by the thinks that she, does and says.

Leonard and his mother are climbing the stairs, while she asks about a. Leonard and Penny are taking it slow. "I see," comments Beverly. After seeing each other for seven s, she wonders if the between them is satisfactory. Leonard reluctantly agrees. "Only satisfactory?" Leonard changes his answer to that it's very hot and then Beverly wonders why he is trying to impress his mother with his sexual prowess. Leonard then asks his mother to do all her in front of the sweet  Mary Cooper.

Enter the apartment, Sheldon goes to greet Beverly who read their paper and called it brilliant. She didn't say anything to Leonard. She feels that is a mother's job to make sure that her 's is not dependent on any else's approval. Mary and Beverly meet and shake hands. Both had good flights, though Mary felt like someone, she's not saying who, was watching over her. Beverly asks if she was kidding.

In her, Bernadette comes into the and finds Stuart in his  taking care of an itch on his. Bernadette doesn't mind him living there, but among the s, he has to wear. Howard then comes in his underwear.

Mary tells Beverly that she must be proud of her. She replies that he is arguing his first in front of the. Oh, you mean Leonard? Yeah, he's terrific. Sheldon starts to show Beverly the he worked out for his. Oops, Leonard's hypothesis. Beverly wonders when Mary first knew that Sheldon was going to have such a remarkable mind. When he was he tried to build the  to supply  for the whole  because he was always concerned about the  of others. This statement confuses Leonard. To power the reactor he had arranged to get some yellow cake from a warlord in , his mother thought he was getting some  from a local. Leonard wants his mother to tell the about how he made a  out of their. Beverly just comments that he broke the vacuum cleaner.

Howard and Raj are playing a in the, while Stuart is reading a  and wearing pants. Bernadette returns after doing a lot of s and declares that she is going to stop being the of three lazy s. She wants them to clean the kitchen from top to bottom including Raj who is doing his  at their house.

Sheldon is showing Beverly s of when he got his. Sheldon doesn't look happy because he just began. Mary says that Shelly does not like change. Penny pops in the door and apologizes that she got caught up at work. She rushes over and Beverly who says, "Oh, okay." Hugging Mary she gets a much sweeter greeting. Penny shows off her that Sheldon announces was made from a re-purposed  drill bit. Leonard denies that and then wants to talk to Sheldon alone. Leonard tells Penny that it came from, though Sheldon is sure that only the came from that store. Penny doesn't care how much Leonard spent on the ring, she thinks.

In Sheldon's, he wonders if he misspoke abut the ring. Leonard feels that Sheldon is hogging the attention from both mothers like a pup or a "Super weaner." Leonard does think he is being a super. Sheldon feels that the situation is like when two mothers faun over the same pup making him a "double mother ", which Leonard also agrees with.

Penny admits that they aren't in any rush to set the date for the. Mary tells her that the moment a they are  in the eyes of. Beverly sighs "Ugh." Mary then asks if the Bible is "ugh" to her. Beverly apologizes and says that she forgets how much a person's mean to them. Mary counters that she read Beverly's that Sheldon sent her about superegos and ids and she wonders what  dropped that on the. . Penny tries to get them together because they both like guys with s. Mary tells her to stay out of this. es and  while Freud wants to talk about why you want to hold your  and crawl back into your. Beverly counters asking how can someone an enlightened as Sheldon comes from someone like his mother. Beverly is not going to like the. While driving to and pregnant with Shelly, she prayed that her  was smarter than his dumb-ass  and she saw a bobble-head of Jesus in the next car nodding yes. Beverly hits her forehead in. Mary tells her to keep doing it and maybe it'll knock some sense into her. Penny wants to change the subject to s or how cute tiny  are. Sheldon comes out saying that it's not his fault that Beverly like him better than Leonard. Leonard point out that his mother likes everyone better than him. Now Penny hits herself in the head.

The Wolowitz guys are cleaning out the kitchen. Raj is working on the. Howard apologizes to them, but Stuart says that Bernadette does work hard around the house. Raj tells Howard that she should stop babying him like his mother did. Howard agrees and that he has to start acting like an in their. He decides to take out the. Picking up the it splits spilling the contents all over the floor.

Beverly and Sheldon are having tea in a and Beverly apologizes for upsetting Mary. Sheldon replies her mother will forgive her since if she doesn't she'll go to. Beverly also mentions how Mary's for Sheldon is diametrically opposed to her own ing style. Sheldon describes her style has doling out affection as a reward for achievement, A proven way to raise a child or train a. Sheldon still turn out very successful under his loving mother. Leonard's s are very successful under Beverly's style while Sheldon's siblings are mouth breathing s. Beverly asks if he would have flourished more under a reward based. Sheldon's mother made him with bits of  in it, so he doesn't care.

Leonard and Penny are talking to Mary as Leonard s that he never got any affection from his mother. Mary assures him that she loved him in her own godless way. and she feels bad about the. Penny assures him that he doesn't have to earn her love and he knew that when he bought her that princess drill bit diamond ring. Mary plans to apologize to Beverly just like a good, though a real Texan would have shot her. Then she asks them if anyone is in the mood for spaghetti and hot dogs. Leonard doesn't feel like he deserves it.

Howard is finished cleaning up the big sticky mess of the garbage spill. Bernadette comes in and tells them how they everything by themselves. Howard agrees, but then first his and then his  sticks to the floor.

Beverly and Mary shake hands and agree to respect each other's beliefs. And Mary will for her. Leonard wants to get his mother quickly back to her. Beverly admits that she always made him earn his affection, but she wants to initiate a new to shower him with unconditional love. When will that start? Beverly then calls him so. She opens her arms and asks him to come to Mommy. They have an awkward hug. Beverly: (Unemotionally) Oh my, son. Leonard: Oh, my mother. Penny: Oh, my God.

Still cleaning up the kitchen, Raj starts to "" from the musical . They all join in singing it enthusiastically. Bernie comes in and immediately leaves.

Critics

 * Jesse Schedeen at IGN - It was also fun to see the dynamic between Beverly and Mary steadily degenerate from polite friendliness to all-out disdain over the course of the episode. Their nonstop barrage of insults and exasperated responses was entertaining, especially with Penny caught in the middle and struggling and failing to keep the peace. It was a rivalry born out of a very natural place of misunderstanding and mistrust, which is more than can be said for some of the contrived arguments on the show...We've been waiting a long time for Leonard and Sheldon's mothers to butt heads, and this episode didn't disappoint in that area. The tension between Beverly and Mary wasn't just amusing, it shone a light on their sons' emotional woes and the challenges they face as adults.

Trivia

 * Third consecutive episode where Amy only appears in one scene.
 * First physical appearance on TBBT set of Beverly since "The Maternal Congruence" (S3E11).
 * This episode aired on both Kunal Nayyar's 34th and Johnny Galecki's 40th Birthday on April 30, 2015.
 * Mary Cooper hasn't appeared in Pasadena since season 5 and hasn't seen Leonard or Penny since then.
 * The idea of Beverly and Mary meeting and facing off has been in the works since season 6 as revealed in s with the s on various occasions, but due to both not being available it was postponed to this season.
 * Sheldon has prepared his mother a bowl of yellow s, the unofficial flower of Texas as in: There's a yellow rose in Texas, that I am going to see...
 * Considering how close Amy and Sheldon are getting, it is usual that she she not sit down with Sheldon's caring mother.
 * Sheldon revealed that Penny's ring was made from a re-purposed   drill bit that they bought online. Interestingly, this also means that he knew that Leonard was going to propose to Penny, yet was still surprised (and troubled) by the engagement in the season 7 finale.
 * Second episode where characters sing as they work. First was "The Work Song Nanocluster".

Quotes

 * Penny: It's so nice, she's going to love it.
 * Amy: Sure, his Mom gets roses. When I want them, they're a "bouquet of severed plant genitals".
 * Sheldon: You act like I didn't get that severed mushroom log on Valentine's Day.
 * Amy: He's right. Roses die, but a moist rotting log will pump mushrooms for two or three magical years.


 * Mary: You can believe that, but God filling an ark with animals two-by-two is nonsense.
 * Sheldon: What did they feed the lions, Mother?
 * Mary: The floating bodies of drowned sinners, of course.


 * Beverly: You’ve been on and off with this woman for seven years and engaged for one year. One has to wonder if there’s a problem. Are you having satisfactory intercourse?
 * Leonard: Yes, Mother.
 * Beverly: Only satisfactory. I see.
 * Leonard: I change my answer. It-it’s amazing. It’s hot. We can barely keep our hands off each other.
 * Beverly: Seems odd to try and impress your mother with your sexual prowess. But then, you always did have that unresolved Oedipal complex.


 * Mary: You must be very proud of your son.
 * Beverly: Oh yes. He recently argued a case before the Supreme Court.
 * Mary: He did?
 * Beverly: Oh, you mean this son. Sure, he’s terrific.


 * Leonard: So Mom. You haven’t seen Penny since she got engaged.
 * Penny: Oh yeah, let me show you the ring.
 * Beverly: Oh, lovely. It must have been very expensive.
 * Sheldon: Oh no, not at all. No, we found a place online that, uh, re-purposes diamond drill bits.
 * Leonard: We did not. That’s not true. Can I speak to you alone for a second.
 * Sheldon: Oh, sure.
 * Leonard: It came from Tiffany’s.
 * Penny: Oh.
 * Sheldon: You mean the box.


 * Mary: The Bible is “uck” to you?
 * Beverly: No. I’m sorry. That was inappropriate. AS a psychiatrist I know how important people’s superstitions can be to them.


 * Beverly: I can’t help but notice how her unconditional love is diametrically opposed to my own parenting strategies.
 * Sheldon: Well, you doled out affection as a reward for achievement; a proven way to raise a child. Or train a rat.


 * Leonard: Not once did my mother ever give me any love or affection for just being myself. I always had to earn it.
 * Mary: Oh Leonard, I'm sure she loves you very much in her own cold godless way.
 * Penny: Yeah, and you certainly don’t have to earn my love.
 * Leonard: Thank you.
 * Penny: Of course you already knew that when you bought me this princess-cut drill bit.
 * Leonard: That’s not what it is.
 * Penny: I know. I know. {Whizzzz.}


 * Beverly: There’s something I need to say to you.
 * Leonard: Oh really? That’s too bad.
 * Beverly: Leonard: I always made you earn my affection, but today I realize that there’s more than one way to raise a child.
 * Sheldon: I taught her that.
 * Beverly: Therefore I would like initiate a new protocol where I shower you with unconditional love.
 * Leonard: Wow. When does that start?
 * Beverly: So needy. Come to Mommy.
 * Penny: It’s okay. Go ahead.
 * Beverly: Oh, my son.
 * Leonard: Oh, my mother.
 * Penny: Oh, my God.


 * Beverly: Mary, I am curious. When did you first realize that your son had such a remarkable mind?
 * Sheldon: Oh, good question. Everybody loves stories about Sheldon Cooper, boy genius.
 * Mary: Well, I’ll have to say when he was thirteen and tried to build a nuclear reactor in the tool shed.
 * Sheldon: Oh, this is a good one.
 * Mary: Now the first thing you have to know about Shelly is ever since he was a little boy he was always concerned with the well-being of others. And he didn’t think it was fair for people to pay for electricity, so he was going to power the entire town for free.
 * Sheldon: Tell her about the uranium. Tell her about the uranium.
 * Mary: Oh, well. Oh, this is adorable. When he arranged to get some yellow cake from Chad, I thought he was talking about Twinkies from one of his friends.
 * Sheldon: Yeah, but wasn't. ‘Cause I didn't have any friends.
 * Mary: No. It turns out that this scallywag was trying to use my Visa card to buy uranium from an African warlord in the country of Chad!


 * Mary: What bull dropped that on the barn floor?
 * Beverly: His name is Sigmund Freud.
 * Penny: Hey, look at that. You both believe in bearded Jewish guys.
 * Mary: Stay out of this.
 * Penny: Mm-hmm.
 * Mary: At least the bearded man that I believe in preaches love and compassion. All yours talks about is why you hold in your poop and want to crawl back inside your Mama.
 * Beverly: It’s fascinating. How can someone as enlightened as Sheldon come from someone like you?
 * Mary: I know the answer. You’re not going to like it.
 * Beverly: Try me.
 * Mary: When I was pregnant with Shelly, I was driving to church, and I was praying to the Lord to give me a son smarter than his dumb-ass Daddy. And I looked over and I saw a Jesus bobble-head in the Subaru next to me nodding yes.
 * Beverly: {Hits herself in the forehead.}
 * Mary: What is that supposed to mean?
 * Beverly: It means – I can’t believe were having this conversation.
 * Mary: Well, do it some more. Maybe you can knock some sense into yourself.