Pierce is asked if he's come "dressed as a millionaire murderer". He's wearing an outfit similar to Patrick Bateman in American Psycho (2000).
Troy is seen wearing Cornelius Hawthorne's ivory toupee (from the episode Advanced Gay (2011) when he and Abed step out of the Dreamatorium.
Andre mentions "Hypercolor and Hammer pants". The Hypercolor line of t-shirts utilized thermochromic dyes, the fabric changed color as it changed temperature.
Pierce introduces the "Trouser Bench", a wearable, automatic chair for the "man on the go." It's played for laughs and is presented as yet another of Pierce's absurd ideas. However, the patent for a wearable chair virtually identical to Pierce's "Trouser Bench" was issued in 1977. Furthermore, by the beginning of the 2020s, multiple companies were selling their own version of the wearable chair.
WILHELM SCREAM: Heard when Troy and Abed are in the Dreamatorium "deweirding" themselves.