In the Lakota nation, Spider is called Iktomi, son of Inyan and older brother to Iya.  He started playing mean tricks that often backfired because others would make fun of his looks.  Because the stories were about a respected (and perhaps feared) deity, it gave children a place to reflect on the morals in the stories.

Iktomi can be seen out of context as an "evil" figure, but if you learn about his full background and stories, you can see that he isn't evil so much as he's a trickster.  Iktomi and the Story of Two Widows and a Red Plum would be an example of how he could be misconstrued.  The Legand of the Dreamcatcher shows his more honorable, dignified side.