nerd teacher [books] quoted Have a Hot Time, Hades! by Kate McMullan (Myth-o-Mania, #1)
Think you know the real story behind the Greek myths? Think again. Most people only …
And now I had my very own underdog.
— Have a Hot Time, Hades! by Kate McMullan (Myth-o-Mania, #1) (Page 155)
This isn't funny as a pun because it doesn't even apply to Cerberus who is anything but an underdog? It doesn't even work as amusing irony because Hades knows who Cerberus is.