Illustrator Tutorial: Halloween Spiders and Webs, Part 2: Here Spider, Spider...

For the spider's upper body, draw a shape (I used the pen tool), and fill it with the same color you used on the lower body shape. Use the Reflect tool to make a copy and flip it at the same time. To do this, double-click the Reflect tool in the tool box to open the dialog (it's on the Rotate tool flyout). Choose Vertical and click the Copy button to add a second shape. Press the right arrow key a few times to move the copied shape to the right; select them both and cmd/ctrl + G to group them.