Amy is aroused by Penny's ex-boyfriend Zack Johnson and is unfamiliar with the feeling. Sheldon thinks she has contracted an alien parasite. Meanwhile, Howard and Raj battle out who is the hero and who is the sidekick in their friendship.
Tropes:
- Arson, Murder, and Jaywalking:Sheldon: Possible explanations for your symptoms are, in descending order of likelihood: hyperthyroidism; premature menopause; hosting an alien parasite; or, and I only include it for the sake of covering absolutely all the bases... sexual arousal.
- Hypocrite: In an attempt to determine who is the hero and who is the sidekick between him and Raj, Howard tries to win the argument by challenging Raj to put his hand in a jar with a tarantula in it, knowing that spiders are Raj's greatest fear. Of course, Raj points out that such a challenge is really stupid, so Howard tries to force him to accept it by asking him what he would do if doing such a thing was the only way to save the world. Unconvinced, Raj retorts by asking Howard what he would do if the only way to save the world was to take a shower in a locker room, allowing other men to see him naked (hinting that this is his friend's greatest fear), to which Howard, after a moment's hesitation, replies that such a scenario is too implausible, as if the one he suggested to Raj not a minute earlier was not also too implausible.Howard: Perhaps. Are you scared?
Raj: No. But it’s a stupid test.
Howard: Oh, really? What if the earth was in danger and the only way to save it was to stick your hand in a jar with a spider?
Raj: Oh, yeah? What if the earth was in danger and the only way to save it was to take a shower in the locker room and let other guys see you naked?
Howard: [He hesitates]... Oh, come on. That’s never gonna happen! - Innocently Insensitive: Sheldon makes an unflattering comparison involving Penny, but she lets it go because she knows Sheldon didn't intend it maliciously, and Sheldon confirms as much right after:Sheldon: I thought [Amy] was a highly evolved creature of pure intellect, like me. But recent events indicate that she may be a slave to her baser urges. Like you.
Penny: I'm just gonna skip over that insult.
Sheldon: ...What insult?
Penny: Yeah, that's why I'm gonna skip over it. - Layman's Terms:Penny: Are you saying that Amy is... oh, what's the scientific word...
Sheldon: Forget science. She's horny. - No, Except Yes:Amy: I'm often flummoxed by current slang. Does "went out" mean "had intercourse"?
Bernadette: Yes.
Penny: No, no. But in this case, yes. - Shout-Out to Shakespeare: Amy talks about "making Shakespeare's metaphorical 'beast with two backs'" (from Othello) with Zack.
- Verbal Tic: Amy finds herself involuntarily saying "Hoo!" upon seeing Zack.
- What Is This Feeling?: Amy tries to understand some odd symptoms she's experiencing: raised temperature, sweaty palms, and vascular throbbing in her ears and genitalia. We know full well that it's sexual arousal from meeting Zack.
- Who's on First?: When Amy tries telling Sheldon about Zack, he repeatedly misinterprets her telling him what she says when she sees Zack- “Hoo!”- as her asking “who?”, leading to him responding “Zack.”.
