Over the years, a bunch of sidekicks came and went - Swee'pea, twin sons, Alice the Goon - but for me The Sea-Hag was the most memorable.
The Sea-Hag appeared rarely in earlier cartoons but was prominent in the later ones. She was weird and nasty and she scared the hell out of me when I was little. After a while, though, she and Popeye started to almost become friends. But even then she was weird, like when she tried to imitate Olive Oyl to get Popeye to be her man, which didn't work.