How is a normal spider bite supposed to look?

Variable: I think a better way to answer this is by saying what an uncomplicated spider bite might look like. Spiders bite and inject some sort of variably toxic venom depending on the type of spider. Some redness, itching and short-lived tenderness at the site is pretty common. Infection is possible. Black widow and brown recluse spiders all have much more toxic venom and can cause a host of bad symptoms.