Quagmire literally loses his manhood when he gets his penis bitten off.
This episode features examples of these tropes:
- Artistic License Biology: How Quagmire's dad gives his own penis as a donor doesn't make sense on different levels but the most gratuitous problem is a sex change would usually not have the penis being amputated (though a lot of comedy shows and jokes imply that this is what happens). The penis' and the vagina's composition are quite similar and that a male-to-female procedure would have the penis and testicles basically inverted rather than be severed.
- Continuity Snarl: Related to Artistic License Biology above. "Quagmire's Dad" has the Title Character explain to Peter how his operation works, namely the fact that his penis was inverted to simulate a vagina, instead of being cut off. This episode implies that it was amputated and has him keeping his severed penis locked away before giving it to his son.
- Groin Attack: Quagmire gets his penis bitten off in a shark attack.
- Laser-Guided Karma: This episode is pretty much Quagmire's long-overdue karma for his sexually deviant ways. Status Quo Is God is also averted, as the end of the episode shows that Quagmire isn't out of the woods yet.
- Lovable Sex Maniac: For the given measure of 'lovable' it's something of deconstruction as we see what happens when the character whose entire life is built around having sex is no longer able to have it. Quagmire tries to find other outlets for urges he's no longer able to act on, but nothing else works and he soon becomes suicidally depressed.