Off the top of my head, I’d give the award to “We Don’t Wanna Grow Up” from Hook as the worst addition to a Williams score. Even though “Jedi Rocks” was composed by Jerry Hey, it still beats out the Hook song. In all fairness, writing a simple song for piano to be performed by a bunch of kids in a play is probably not going to elicit a memorable piece of music…I just wish they had ditched both the songs and added more score to the original release (as well as track titles).
As far as Williams’ odder work goes, I think I’ve been pretty charitable. “Heartbeeps” had its moments and I had no problem with the more pop-oriented music in “SpaceCamp”.