The snail appeared next to Slime Princess when she says "Yay", in the scene where they are tricking the Ice King so they can get out of the cage.
This episode was originally titled to be "Meet the Ice King", as this is the Ice King's first appearance in this show.
Ice King: Why are you doing this? They were just warming up to me!
Finn: No! That is not the case! You're nuts, man! I don't know how to help you. Maybe that's because I'm just a simple dude. You should talk to someone with more life experience. Like Jake!
Jake: Whoa whoa whoa, Finn! Don't dump the Ice King on me!
Ice King: Whaaat? Who dares enter the Ice Kingdom!
Finn: Awwww. Ice King's here.
Ice King: Do you know WHY I'm here? Do you know what Ice King MEANS?
Jake: Yeah... A BIG NERD.
Finn: Ooohh, holy cow!
First episode that Princess Bubblegum didn't appear.
The title of this episode "Prisoners of Love" is taken from the Mel Brooks' movie The Producers. It is the name of the play (and the song) from a play that the main characters, Max Bialystock & Leo Bloom create when in prison.