Aired Thursday June 20, 1:30pm - 2:00pmon E4 +1

The Big Bang Theory

Series 4 Episode 10: The Alien Parasite Hypothesis

Amy finds she has sexual feelings for Penny's ex-boyfriend Zack while Koothrappali and Wolowitz try to prove who would be the better superhero.

Original air date
Cast and crew
  • Mark CendrowskiDirector
  • Johnny GaleckiLeonard Hofstadter
  • Jim ParsonsSheldon Cooper
  • Kaley CuocoPenny
  • Simon HelbergHoward Wolowitz
  • Kunal NayyarRaj Koothrappali
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