Parasite Hypothesis: [s4e10] The Alien

Dismissed by Amy (despite Sheldon's "testy bark of an old biddy" comment).

Amy attempts to satisfy her urges by approaching Zack, telling him she is "130 pounds of raging estrogen" longing to "make Shakespeare's metaphorical Beast with Two Backs".

The "cold, harsh truth" they eventually accept. Iconic Moments & Quotes [S4E10] The Alien Parasite Hypothesis

Sheldon famously declares 73 the "best number". It is the 21st prime number. Its mirror (37) is the 12th prime. In binary, it's a palindrome: 1001001 .

Sheldon’s preferred theory, as he finds it more plausible than the final option. Dismissed by Amy (despite Sheldon's "testy bark of

Howard and Raj fight over who would be the superhero and who would be the sidekick after a lab tech is bitten by a radioactive rat. Production Trivia

Fans often point out that Sheldon and Amy eat lunch in the lab while Amy is slicing brain tissue—a major violation of safety protocols. Iconic Moments & Quotes Sheldon famously declares 73

Amy informs Penny that the iconic heart shape is actually based on the shape of a female’s buttocks when bending over. The Alien Parasite Hypothesis | The Big Bang Theory Wiki