1. "The Bicycle Man"

 

The two-part episode was the signal that Diff'rent Strokes was about to dabble in darkness. In fact, the first four entries here were all two-parters. Even in "Hooray for Hollywood," a vacation episode featuring a Hasselhoff cameo, the kids nearly get blown up on the Knight Rider set. But no episode sticks haunts Gen Xers like "The Bicycle Man," which cast Gordon Jump as a pedophile who preys on Dudley. It was a gutsy role for the WKRP in Cincinnati actor, and one we're thankful he only portrayed for one hour.

2. "Sam's Missing"

 

Sam, with his freckles and strawberry bowl cut, joined the cast in season six (during that Hasselhoff tale, actually). The poor kid was often the center of suspenseful plots, as writers endangered him again and again. In "Sam's Missing," a man named Donald Brown (Royce D. Applegate) kidnaps Sam to replace his dead son. "I will kill your parents, Sam," he warns the redhead.

3. "The Hitchhikers"

 

Kimberly and Arnold hitchhike home to make it in time for Mr. Drummond's birthday party. The man who picks them up tries to force himself on Kimberly, who swings a stone obelisk in an attempt to fight off her attacker, as Arnold desperately tries to pick the lock on the door. Arnold races home for help. The police hypnotize Arnold for the location of their kidnapper. The assaulter is arrested just in time for the party. Before both episodes of this two-parter, Conrad Bain addressed the audience to warn families of the dangers of hitchhiking.

4. "The Adoption"

 

Whitman Mayo, best known as Grady from Sanford and Son, breezed into the boys' lives just as Mr. Drummond was about to adopt the two. He claimed to be their cousin, Jethro, seeking a piece of their inheritance. Turned out, he was a conman.

5. "Bulimia"

 

In her final episode, Dana Plato's Kimberley struggled with an eating disorder. Plato herself dealt with an eating disorder, perhaps inspiring the writers, who wisely steered away from their original script title, "Baby, Where Did Our Food Go?"

Image: The Everett Collection

6. "The Reporter"

 

After Arnold's deep-digging investigative journalism for the school paper unearths a drug dealer, First Lady Nancy Reagan visits the classromm to deliver her "Just Say No" message. It marked Mrs. Reagan's first acting performance since 1962.

Image: The Everett Collection

7. "A Special Friend"

 

Arnold and Sam pal around with an epileptic street performer. After she has a seizure, the kids make jokes. Overhearing their crude humor, housekeeper Pearl (Mary Jo Catlett ) reveals that she, too, has epilepsy.  

8. "The Peacemaker"

 

Speaking of crude jokes, Andrew Dice Clay, in his television debut, turns up as a suspiciously old classmate of Willis, who finds himself in the middle of a high school gang beef. Fearing for his safety, he packs heat. Paranoid, Willis nearly shoots Mr. Drummond, mistaking him for an intruder. 

9. "Cheers to Arnold"

 

The final two episodes on our list both dealt with alcohol abuse. Here, one of Arnold's school buddies, Ricky, sips liquor from a thermos and pressures her peers into taking a slug. Arnold must convince his friend to clean up. 

10. "A Growing Problem"

 

Mr. Drummond's stern rules on drinking force Willis to move in with a friend, Jerry. "I love Dad, but he's just impossible to live with," Willis says. "So are you, but I do it," Arnold replies. Jerry drives drunk, and a car crash quickly sobers up Willis. "He's real bad, he's in a coma," Willis tells his dad. "They wouldn't let me see him, the doctors said there's nothing I can do and to go home. This is my home, isn't it? Dad, I want to come back, can I?"

SEE MORE: 13 attention grabbing titles of 1970s and '80s after school specials

 

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