Bluto

Bluto is a big, nasty sailor who loves to pester Popeye and try to win the heart of his crush Olive Oyl. He varies between being a big strong brute of a man and very bold and smart - he is always depicted as extremely strong (often superhumanly so). However, after he usually beats up Popeye, Popeye finds a can of spinach, eats it, gets stronger, and beats Bluto into unconsciousness.

History
Despite Bluto and Popeye's legendary rivalry, it is often shown that Bluto was once a friend of Popeye but the two became bitter enemies due to the fact that both were in love with Olive Oyl - while Popeye was a gruff but well-meaning sailor Bluto was always rough and mean, so naturally he began to pester Popeye and even when Olive Oyl clearly made her choice he wouldn't let them be: going as far as regularly kidnapping Olive Oyl, expressing his affection as only the big brute can.

From time to time this friendship is rekindled, though it seldom lasts long, although Bluto is widely seen as Popeye's nemesis he is not actually the offical archenemy of the sailor - that honor belongs to The Sea Hag: who Bluto has occassionally worked for both willingly and as a mind-washed slave.

Live Action Movie
Bluto was the main antagonist of the live-action Popeye movie where he was not only his traditional bullying self but also a shameless criminal who terrorized the fishing community Popeye came to, this movie was rather unique in that Popeye hated spinach and near the end Bluto's own stupidity got the best of him when he force-fed Popeye spinach out of spite: the resulting transformation scared Bluto so badly the big bully literally turned yellow and swam out into sea.

Trivia

 * In a series of 1960's Popeye cartoons, King Features Syndicate operated under the mistaken assumption that they had lost the rights to the name, 'Bluto'. As a result, Popeye's rival was named 'Brutus' instead, even on merchandise.