Just a thought since we do love how the series have treated our every-man Miles, what about Deanna? Off the top of my head:

• Alien energy makes her pregnant
• Alien consciousness takes over her body and a few of them take over the ship
• Telepath makes her super horny and she ages rapidly
• She loses her empathic abilities and isn't sure what she's good for without them
• She becomes a cake
• She devolves into a (fishy?) prey species

I bet there are more, but these are the ones I could think of quickly.