At Elzar's restaurant the blackboard outside advertised 'Them! Any style.' Inside Fry and Leela eat large ants. The 1954 film Them! was a film about giant ants.
After promising not to tell anyone about Amy's marmoset costume, Geunter makes the "speak no evil" gesture.
This marks Guenter's first appearance since season 2 episode 2, "Mars University" which aired October 1999.
Amy et al. running through the zoo are chased by barking thylacines. Thylacines were brought back from extinction by the Encyclopod in the feature-length episode Futurama: Into the Wild Green Yonder (2009). The thylacine (aka Tasmanian tiger, aka Tasmanian wolf) was an apex carniverous predator in Australia and Tasmania until it went extinct around 1930. As a marsupial it was more closely related to a koala than to a wolf or tiger.
The only appearance of the oft-mentioned Sean, Leela's ex-boyfriend.