Dr. Doom- Fantastic Four #60

 In Fantastic Four #57  Dr. Doom tricks the Silver Surfer into standing before a machine that steals his power, transferring it to Doom. In Fantastic Four # 58 Doom uses Silver Surfer's board to fly to New York and attack the Fantastic Four. One by one all of the members of the Fantastic Four fall to Doom's new power- but he does not kill them. Instead, Doom tells them that resistance against is plans is futile and gloats about his victory. 

In Fantastic Four #59 Doom brings darkness to a village in Europe, freezes the Aegean Islands, and mutates an African gorilla into a rampaging monster. He enjoys showing off his new power but thinks it is finally time to take over the world- enter Fantastic Four #60. 

Doom stealing Silver Surfer's power qualifies as a villainous move because, at this point in Marvel Canon the Silver Surfer has just saved the entire world, including Doom himself, from Galactus. Doom is basically saying "thank you" to Silver Surfer by stealing the powers that were used to save the world- and using them to try and take over that same world. 

Fun Fact: Doom also steals the Silver Surfer's power twice in the 1994 Fantastic Four television show- and, oddly, both instances occur during season finales (1 and 2). 

Worth a mention: Dr. Doom also uses an item called the Cosmic Cube to steal power from Galactus. Doom then creates an alternate reality where he is crowned Emperor Doom and rules with Storm by his side.