The Slippery Slope fallacy is when an arguer exaggerates one step leading to further unacceptable steps or final step, regardless of how likely it is to do so.(IEP, Dowden)
Example:(IEP, Dowden)
Mom: Those look like bags under your eyes. Are you getting enough sleep?
Jeff: I had a test and stayed up late studying.
Mom: You didn’t take any drugs, did you?
Jeff: Just caffeine in my coffee, like I always do.
Mom: Jeff! You know what happens when people take drugs! Pretty soon the caffeine won’t be strong enough. Then you will take something stronger, maybe someone’s diet pill. Then, something even stronger. Eventually, you will be doing cocaine. Then you will be a crack addict! So, don’t drink that coffee.