A Slippery Slope is a fallacy in which change in one direction is assumed to lead to further disastrous change in the same direction. Depending on how extreme the slope gets, some of these can be quite humorous. Case in point is a series of ads from DirectTV in which the basic narrative of the ad is a series of slippery slopes describing all the horrible consequences that will follow if one doesn't purchase DirectTV. While these are intentionally absurd, they are still a good model of the kind of flawed reasoning exhibited by this fallacy.