"Mr. B Natural" is "the spirit of music," and also happens to be played by "Betty Luster" with a high-pitched voice and a certain shapeliness... Once the "riffers" have gotten over this (more or less), there's something kind of fun about the short's hard-selling music as a way to build confidence and resolve youthful awkwardness, by buying a pricy instrument (the "riffing" of the instrument factory sequence is particularly fun) and joining the school band. After the short, Tom and Crow debate whether Mr. B Natural is a man or a woman.
Despite an opening sequence with a speeding truck ("To prove how tough this Ford is, we're pitting it against the Colossal Beast!"), "War of the Colossal Beast" takes its own deliberate time (the "riffers" are constantly pointing out how Bert I. Gordon spares us nothing) reintroducing the sixty foot-tall Colonel Glen Manning, the matte effects that make him that tall as shoddy as ever. He survived falling off Boulder Dam if with part of his skull now sticking out of his face to be washed down-river to the Gulf of California, where he proceeds to hide in Mexican mountains (perhaps helping to call back to the opening "host segment," where Joel and the bots come up with names for new kinds of Mexican food) and grab food trucks off the road. ("Ah, nothing. This is the last time I hijack an organic food truck!") News of this eventually reaches Glen's sister Joyce (although I can recall a comment in "The Amazing Colossal Man" that Glen didn't have any family and his fiancee was the only person in his life; of course, in this movie even Glen Manning himself is being played by someone else; Mike Nelson returns as Glen with a slightly better "bald" effect than before commenting on how "he" was replaced), and she leads the US Army into Mexico to capture Glen with a truck full of drugged bread. (The drugged Glen may collapse right on a Mexican policeman; the movie doesn't seem quite clear on the issue.) Taken back to Los Angeles as different government branches pass the buck as to just who's responsible for him ("Bert I. Gordon sticks it to the man!"), Glen is tested to see if his mind is there but to no avail. At last, Glen escapes from the hangar he's chained up in and makes his way to a Los Angeles park (as Joel has great fun with the call sign of a local TV station, KTLA), where he terrorizes a bus full of school children until Joyce gets to him. Glen speaks her name at last instead of bellowing, but at sixty feet tall and with part of his skull sticking out of his face the best thing he can think of doing is grabbing some nearby power lines and vaporising himself as the film shifts to watery, blurry, pastel colour. As far as Mystery Science Theater episodes go, I'd say this one is as good in its own way as the "original."