Which of the live action Teenage Mutant Ninja Turtles movies had the best rap song for its theme?
The contenders are
1. Partners in Kryme - Turtle Power
2. Vanilla Ice - Ninja Rap
3. Psychedelic Dust featuring Loose Bruce - Turtle Jam
Now, a good theme song needs to have some applicability to the movie it's part of (unless it doesn't - as the Veggie Tales veggies state in "This is the Song that Runs under the Credits": There should be a rule that the song under the credits/Remotely pertains to the movie’s basic plot/That rule has not been made).
However, when determining which of the three Ninja Turtle raps are the best, it's clear that the first place to look is at how well it pertains to the movie. On that score, "Turtle Jam" from the third movie fails utterly. It barely even lets you know that we're dealing with Mutant Ninja Turtles. The rhymes are uninspired and the similes lacking ("like my man DeNiro" makes no sense except as a lazy rhyme). Listening to the song, you'd get the idea that the turtles are from the sewer and they "kick some shell." That's about it. The turtles do get name checked, but you learn nothing about their personalities or situations. Less than 10 percent of the lyrics could be changed, and the song could be about Charlie's Angels, the cast of Firefly, or even the Brady Bunch on a particularly aggressive day.
Vanilla Ice's "Ninja Rap" suffers from a similar problem, but almost gets a pass because in the movie, it's part of the plot and the conceit of the song is that it's improvised on the spot, during an actual battle. Thus, Mr. Ice would not have time to understand the players or the situation. The song works as a nice, generic rap about why ninjas are cool and should win fights against bad guys, so in the context it is presented, it doesn't fail utterly.
However, it was done by Vanilla Ice.
Partners in Kryme's "Turtle Power", on the other shell, stands head and shoulders above them all. After the song you know the basic personalities of the various characters, the set up for the movie's plot, what's at stake - and you've learned a valuable lesson about how to "stand for what you believe in/and find the strength to do what's right." Clever rhymes, specificity, and a good moral that's not shoved down your throat. It succeeds on all levels.
Thus, the first is the best. Now Western Civilization can rest at ease.