Amy being attracted to Zack and her working with Sheldon on figure it out was a pretty fun story. They had a lot of great moments, I especially liked her confronting Sheldon about being jealous and him taking brain slices instead of his sashimi. Her conversation with Zack where she changed her mind was also really well written. I think though my favorite part was Howard and Raj fighting for who will be a superhero without even touching each other. That scene was just hilarious.
Review of The Alien Parasite Hypothesis
