https://www.youtube.com/watch?v=78ZOm-A5JIM
my answer changes from day to day but my all-time answer might be "Memo To Human Resources". The Spine was my first TMBG record (yeah i watched a lot of Homestar Runner as a kid, how did you know) and, on an album full of high-intensity songs, this sort of dreamy, oxygenated easy listening song about a disgruntled office worker threatening to do something rash was such a singularly weird and memorable song for Small Iris
https://www.youtube.com/watch?v=S7BxKC9RmiU
runner-up: "Circular Karate Chop" is such a great little portrait of weird awkward teen masculinity that has so many odd little bits going on in it. Nanobots is maybe my favorite 2010s TMBG album and this one's a highlight