Samantha "Sam" Star is Patrick Star's older sister. She was lost in a surf when she and Patrick were kids, and Patrick possibly forgotten about it, due to the fact that in "Something Smells," he says he doesn't have a sister. It is possible Patrick just forgot about her. Her only appearance so far was in "Big Sister Sam."
Sam is a large, overweight, and muscular sea star with coral-pink skin. She is roughly twice the size of her younger brother Patrick. She has black hair which she wears in a side ponytail that is fastened with a pale lime-green scrunchie. Her outfit consists of a violet-blue top with flowers that are the same color of her hair scrunchie, as well as a matching skirt. Sam has a very low and deep voice; similar to a caveman's (despite usual females having much higher voices). She often calls herself "Sister Sam." She can literally put on her mean face whenever she completely loses her temper by turning her head around. She becomes very aggressive and destructive and can end up destroying anything in her path.
Sam is shown to be highly aggressive by her clarity. This can be true as she is easily provoked by any person she doesn't recognize. However, she expresses a brotherly bond with her younger brother and defends him from the other neighbour Squidward when she mistaken physical contact as aggression. In addition to her supportive behavior, her level of intelligence is relatively lower than Patrick's as she speaks incomplete language and has no regard for other people. She talks in third person. Sam is the only known sibling to Patrick.
Sam was shown only in "Big Sister Sam" and it is unknown if she will ever appear again.
In "Something Smells," when Patrick is going on about his breath, he says, "What will my sister say? Oh wait. I don't have a sister." He might have forgot Sam or keeping her as a secret because "Something Smells" was before "Big Sister Sam."
Sam mispronounces "brother" as "brubber" and "decorate" as "blecorate."
Strangely, Sam is voiced by a male actor (Bill Fagerbakke), but she is a female in the episode.
Yellow square touch brubber! Makes Sister Sam MAD!
If Big Nose no like sand, BIG NOSE MOVE!
Those boys mean! They pick on Sister Sam!
You mean... blecorate?
Sister Sam rearrange NO!
Yellow square make brubber's eyes water!
MEANIES GO HOME!
Meanies is mean.
Patrick okay! Sister Sam feel bad. Sorry she hurt Patrick. She protect little brubber. She go now.