Your mom.
The spider you are describing is likely the black widow spider. It is known for its shiny black body with a red hourglass-shaped marking on its abdomen. This spider is venomous and can be found in various parts of the world.
I believe it is a type of jeweled spider.
The male green jumping spider has a dark red head and a bright green body. The scientific name for this spider is Mopsus Mormon.
6,000 on its butt.
The spider you are describing sounds like a common household spider known as the "brown widow." Brown widow spiders have a distinct color pattern with a brown abdomen, brown legs, and a black head. Their appearance can resemble a fly due to the coloration of their body segments.
The distinguishing feature of a black spider with a brown butt is its unique coloration, which sets it apart from other spiders that may have different color patterns or markings.
Don't mind if I do. (Yum.)
This is probably a Red-Backed Jumping Spider. The male has a black body with a bright red abdomen. The female is the same, but the red abdomen has a black stripe. They're found all over the United States. If you want pictures of them, you can find them online at http://kaweahoaks.com/html/spi_phidippus_johnsoni.html.
Identifying spiders is difficult to do without knowing more than just the spider's color.. Body type, the presence or absence of hair, and where the spider is found can all help to make a positive identification. A spider with a black body and brown legs is likely to be a common house spider, which is not dangerous.
I think its a white tail :D
An entamologist would have to see it to give you an id. Part of it is counting it's eyes.
a redback spider