"Day of the Snowmen" finds the Possibles (and a visiting Ron) under siege one wintry day. The attackers? Toxic, killer snowmen. Let me type that again in case you weren't paying attention: The Possibles (and Ron) must ward off toxic, killer snowmen.
As it has been proven by the direct-to-video Jack Frost films, toxic killer snowmen make for weak entertainment. This episode does nothing to turn the tide. In fact, it doesn't so much play like a bad horror movie as it does a parody of bad horror movies, but without those pesky laughs getting in the way. There's the ludicrous revelation about one of the trapped characters (in this case, local weather lady Summer Gale). One of the characters (their identity concealed so as to preserve their dignity) foolishly remarks "It's over", an instant invitation for more badness to occur. And if you've sat through even one horror movie, the final shot shouldn't be anything even remotely resembling a surprise.
It's interesting to note that the weather machine from "Job Unfair" makes a return. The respect shown for continuity is about the nicest thing I can say here.
Even at 11 minutes, "Day of the Snowmen" seems drawn-out. Instead of watching it, there are much better ways to spend your free time, like doing your homework, cleaning out your bathtub or (in the spirit of this episode) watching ice freeze.